Question 1

Indian Railways – Historical administrative structure For effective administration, into how many railway zones was the Indian Railway system traditionally divided (legacy classification used in many exam standards)?

Accepted Answer

Introduction / Context: Exam questions on Indian Railways often reference the legacy administrative structure. While the present-day network has expanded to many more zones, older standards and textbooks commonly cite an earlier configuration. This item checks recall of that conventional division used in numerous competitive exams and civil engineering question banks. Given Data / Assumptions: The question explicitly asks for the traditional/legacy number of zones used for effective administration, not the current count. Options range from four to nine zones. We assume the context of historical organization commonly quoted in older syllabi. Concept / Approach: Historically, Indian Railways described an administrative structure with nine zones in many standard references. Although reorganizations created additional zones later, multiple exam banks still use the nine-zone figure as the 'correct' legacy answer. Understanding the historical context prevents confusion with contemporary figures. Step-by-Step Solution: Identify the era/context intended: legacy administrative divisions.Recall that many classic references describe nine zones for effective administration.Select the option matching this legacy figure: nine railway zones. Verification / Alternative check: A quick cross-check with traditional exam-prep material and older handbooks confirms that 'nine zones' is the commonly accepted answer in the legacy context. Modern counts are higher but are not the target here. Why Other Options Are Wrong: Four/Six/Seven/Eight zones: These do not match the historical nine-zone classification found in standard older references. Common Pitfalls: Students sometimes answer using the current number of zones. The key is noticing the exam’s legacy framing ('for effective administration' as stated in many older texts), which points to the traditional nine-zone answer. Final Answer: Nine railway zones

Question 2

Selection criteria for sleepers (railroad ties) Which factors are considered while deciding the type of sleeper to use on a railway track?

Accepted Answer

Introduction / Context: Sleepers (railroad ties) transfer loads from rails to ballast, control gauge, and influence ride quality and maintenance. Selecting an appropriate sleeper type (timber, steel, prestressed concrete, etc.) requires evaluating several engineering and economic parameters. Given Data / Assumptions: The question lists four practical factors: handling/fastening, bearing area, costs, and structural strength. We assume conventional ballasted track with standard fastening systems. Concept / Approach: Sound engineering selection requires a holistic view: constructability, performance, and life-cycle cost. Each listed factor contributes to track stability and maintainability. Therefore, the comprehensive answer includes all. Step-by-Step Solution: Check engineering practicality: ease of rail fixing/removal reduces possessions and improves maintenance productivity.Check structural need: adequate bearing area spreads load, limiting ballast pressure and settlement.Check economics: initial procurement and long-term maintenance costs drive life-cycle performance.Check strength: sleepers must act as beams to resist bending between ballast contact points.Conclusion: all listed factors matter simultaneously → 'All the above'. Verification / Alternative check: Codes and permanent-way manuals outline multi-criteria selection including durability, maintainability, and structural capacity, aligning with the listed factors. Why Other Options Are Wrong: Choosing any single factor ignores the multi-criteria nature of sleeper selection. Track design is not optimized if one dimension dominates at the expense of others. Common Pitfalls: Focusing only on initial cost and neglecting maintenance or long-term performance; or prioritizing strength without considering fastening compatibility and ease of replacement. Final Answer: All the above

Question 3

History of Indian Railways – Metre-gauge adoption In India, the metre-gauge (MG) permanent way was formally adopted in which year?

Accepted Answer

Introduction / Context: Knowledge of historical milestones helps engineers understand why legacy infrastructure varies by region. Metre-gauge (1000 mm) lines were built extensively in the subcontinent, and many competitive questions ask the year of adoption. Given Data / Assumptions: We are seeking the formal adoption year of the MG permanent way in India. Options focus on the mid-to-late 19th century period. Concept / Approach: Historical exam keys and classic permanent-way texts commonly cite 1871 as the year associated with MG adoption policy and rollout momentum, preceding major MG construction (e.g., Rajputana–Malwa lines in the 1870s). Step-by-Step Solution: Identify the typical reference year used in standard question banks.Correlate with known MG expansion occurring in the early-to-mid 1870s.Select 1871 as the formal adoption year. Verification / Alternative check: Multiple railway history compendiums and exam resources point to the early 1870s decision framework, commonly rounded to 1871 in MCQs. Why Other Options Are Wrong: 1855/1860/1866: too early relative to MG policy adoption and network build-out timelines. 1875: post-dates standard references typically quoted in exams. Common Pitfalls: Confusing first openings/sections with the formal adoption year; mixing construction milestones of specific lines with the policy adoption date. Final Answer: 1871

Question 4

Steel sleepers – principal disadvantages Which of the following best summarizes the main disadvantages of steel sleepers used on railway track?

Accepted Answer

Introduction / Context: Steel sleepers were widely used due to their strength and uniformity. However, they come with specific drawbacks that influence maintenance and life-cycle costs. This question assesses awareness of those disadvantages. Given Data / Assumptions: Disadvantages listed include corrosion and lug failures. We consider typical ballasted track conditions in Indian climates. Concept / Approach: Steel is susceptible to corrosion, especially in humid, coastal, or aggressive environments. Mechanical features like lugs (used for holding fastenings) can be damage-prone under repeated load and maintenance operations. Step-by-Step Solution: Evaluate corrosion: legitimate concern → steel sleepers need coatings/painting and still corrode over time.Evaluate lugs: repeated stress, tamping, and fastening works can cause breakage or splitting.All listed issues are recognized in practice → choose 'All the above'. Verification / Alternative check: Maintenance manuals note corrosion mitigation requirements for steel sleepers and document lug damage incidents, validating these drawbacks. Why Other Options Are Wrong: Any single item does not capture the composite disadvantage profile found in field practice. Common Pitfalls: Assuming that protective coatings eliminate rust risk entirely; in reality, coatings reduce but do not eliminate corrosion, especially where maintenance damages the protective layer. Final Answer: All the above

Question 5

Ballast maintenance practice Where is ballast packing primarily carried out to provide support and maintain track geometry?

Accepted Answer

Introduction / Context: Ballast supports sleepers and enables drainage while allowing geometric adjustments through packing and tamping. Understanding where packing is focused helps in appreciating maintenance operations and the mechanics of track support. Given Data / Assumptions: The options distinguish different locations around sleepers and rails. We assume conventional ballasted track and standard tamping procedures. Concept / Approach: Ballast packing is primarily performed beneath sleepers to achieve proper bearing and correct levels, cross-levels, and alignment. Although shoulders and sleeper ends are also important for lateral resistance and stability, the essential act of 'packing' to correct levels happens under the sleeper. Step-by-Step Solution: Recognize the purpose of packing: restore and maintain geometry by supporting sleepers evenly.Identify the critical contact zone: the sleeper–ballast interface below the sleeper.Select 'Under sleepers' as the primary locus for packing. Verification / Alternative check: Track maintenance manuals and tamping machine operations describe insertion of tines and compaction under sleepers as the core process of packing. Why Other Options Are Wrong: Near ends/shoulders: important for stability but not the principal definition of packing. Between rails only: packing is not limited to this region; it must support each sleeper fully. Common Pitfalls: Equating shoulder maintenance with packing; shoulders resist lateral movement, while packing under sleepers primarily corrects geometry. Final Answer: Under sleepers

Question 6

Preventing rail creep with steel sleepers To minimize rail creep on steel-sleepered track, rails are secured using clips, bolts, and how many keys?

Accepted Answer

Introduction / Context: Rail creep (longitudinal movement of rails) leads to joint gaps and geometry defects. On steel sleepers, particular fastening arrangements help resist this movement by providing adequate longitudinal restraint. Given Data / Assumptions: Steel sleepers are assumed to use clips, bolts, and keys. We are focusing on the typical number of keys employed to prevent creep effectively. Concept / Approach: Traditional steel-sleeper arrangements often employ double-keyed systems—two keys—providing opposed bearing to reduce longitudinal slip. This symmetric restraint enhances holding power compared with single-key arrangements. Step-by-Step Solution: Recognize that creep prevention relies on friction and mechanical interlock.Double-key (two keys) systems brace the rail foot on both sides.Hence, select 'Two keys' as the standard answer used in many exam references. Verification / Alternative check: Old permanent-way manuals and question banks commonly specify two keys for steel sleeper anti-creep arrangements. Why Other Options Are Wrong: One key offers less restraint; three or four keys are not standard practice for typical steel-sleeper fastenings and would be impractical. Common Pitfalls: Assuming heavier clips alone are sufficient; proper keying pattern is critical to creep control. Final Answer: Two keys

Question 7

Standard rail lengths worldwide 30 m-long rails are (historically) used predominantly in which country's railway practice?

Accepted Answer

Introduction / Context: Rail lengths have varied by country due to manufacturing capabilities, handling limits, and legacy standards. Recognizing typical lengths helps avoid confusion when solving track design and maintenance problems that reference foreign practices. Given Data / Assumptions: The question targets the 30 m standard length and asks which country historically used it. We consider legacy jointed-track practice rather than modern long-welded rail (LWR/CWR). Concept / Approach: Historically, the U.K. adopted approximately 30 m rail lengths in certain eras as an efficiency compromise between joint reduction and handling practicality. By contrast, India traditionally used 13 m and later 26 m; U.S.A. commonly referenced 39 ft; Russia and Pakistan also had different standards. Step-by-Step Solution: Match 30 m to known legacy standards internationally.Associate 30 m with British practice historically cited in exam literature.Select U.K. as the correct option. Verification / Alternative check: Permanent-way comparative tables and exam guides list 30 m for the U.K., aligning with this answer. Why Other Options Are Wrong: India/Pakistan: typically 11.89–13 m and 26 m (later), not 30 m. U.S.A.: 39 ft (≈11.89 m) common historically. Russia: often 25 m or other standards. Common Pitfalls: Confusing modern CWR practice with historic jointed lengths; mixing India’s 26 m rails with the 30 m figure. Final Answer: U.K.

Question 8

Crossing geometry with parallel sidings If D is the perpendicular distance between two parallel sidings and α is the acute crossing angle, what is the distance between the noses of the crossings measured parallel to the main track?

Accepted Answer

Introduction / Context: Turnout and crossing design requires translating a perpendicular separation into a longitudinal spacing along the main track. Trigonometric relations provide the conversion using the crossing angle. Given Data / Assumptions: D = perpendicular spacing between parallel sidings. α = acute angle of crossing with the main track. Need: distance between noses along the main track direction. Concept / Approach: Draw a right triangle where the opposite side is D (perpendicular gap) and the angle at the main track is α. Then tan α = opposite/adjacent = D/L, where L is the required longitudinal spacing. Rearranging gives L = D / tan α = D cot α. Step-by-Step Solution: Let L = distance along main track.tan α = D / L.Therefore, L = D / tan α = D cot α.Hence the correct expression is D cot α. Verification / Alternative check: As α becomes smaller (flatter crossing), tan α decreases, so L increases—physically consistent since a flatter crossing requires longer longitudinal development. Why Other Options Are Wrong: D tan α: gives transverse increment for a given longitudinal run, not the required along-track spacing. D sec α or D cosec α: do not match the right-triangle projection for this geometry. None: invalid because a correct expression exists. Common Pitfalls: Interchanging tan and cot; mixing up which side of the triangle corresponds to D or L. Final Answer: D cot α

Question 9

Preferred rail section for heavy Broad Gauge main lines On B.G. main lines carrying maximum traffic loads, which rail section (weight per metre) is generally preferred?

Accepted Answer

Introduction / Context: Heavier rail sections better resist bending, wear, and contact stresses on busy main lines. Indian Broad Gauge (B.G.) routes with high axle loads and traffic intensity typically employ heavier rail weights. Given Data / Assumptions: Units are weight per metre (kg/m) for standard rail designation. The question asks for the range suited to heavy B.G. main lines. Concept / Approach: B.G. main lines under maximum traffic loads commonly adopt rail sections in the range of approximately 45 to 57 kg/m. This ensures adequate section modulus and durability, reducing frequency of renewals and maintenance. Step-by-Step Solution: Identify the options with correct units (kg/m vs kg/cm).Recognize that 44.7–56.8 kg/m aligns with heavy main-line practice.Select 44.7 to 56.8 kg/m as the preferred range. Verification / Alternative check: Track standards and procurement records consistently list heavier rails for busy routes, matching the 52 kg and 60 kg class commonly referenced (approximate to the given range). Why Other Options Are Wrong: 29.8–37.3 kg/m: lighter sections suited to lighter traffic or branch lines. Options in kg/cm: unit error; rails are specified in kg/m. None: incorrect because a suitable range is provided. Common Pitfalls: Missing unit consistency; confusing nominal catalogue weights with exact in-service designations. Final Answer: 44.7 to 56.8 kg/m

Question 10

Primary functions of sleepers in railway track Which statement best describes the main functions performed by sleepers (railway ties)?

Accepted Answer

Introduction / Context: Sleepers are critical structural elements of ballasted track. They ensure that rails are correctly positioned and that vehicle loads are efficiently carried to the track foundation while maintaining track geometry over time. Given Data / Assumptions: The listed options are the canonical functions assigned to sleepers in permanent-way engineering. We assume standard gauge control and ballast-supported track construction. Concept / Approach: Each listed function is essential: sleepers support rails, keep the gauge fixed by holding the rails at a precise spacing, and distribute vertical and lateral loads into ballast, thereby reducing pressure and preventing excessive settlement. Step-by-Step Solution: Confirm structural support: rails rest on sleepers which transfer loads downward.Confirm gauge control: rail seats and fastenings hold the exact spacing.Confirm load distribution: sleepers spread wheel loads across ballast contact area.Hence, all functions apply → choose 'All the above'. Verification / Alternative check: Textbook definitions and codes consistently describe these three as the principal sleeper functions, sometimes adding damping and lateral restraint as secondary roles. Why Other Options Are Wrong: Picking any single function is incomplete; sleepers perform multiple simultaneous roles to keep track safe and serviceable. Common Pitfalls: Overlooking the gauge-holding role or assuming that ballast alone ensures spacing; without sleepers and fastenings, gauge cannot be reliably maintained. Final Answer: All the above

Question 11

Fastenings for rails on steel sleepers In permanent-way engineering, when rails are seated on pressed steel or fabricated steel sleepers, by which fastening method are the rails typically secured to the sleeper seat?

Accepted Answer

Introduction / Context: Steel sleepers are widely used in permanent-way construction because they provide a stable seat to the rail and offer better resistance to longitudinal and lateral forces. The way a rail is fastened to a steel sleeper differs from timber sleepers and is fundamental to track safety, gauge retention, and maintenance economy. Given Data / Assumptions: Rails are seated directly on steel sleeper seats that have formed lugs or jaws. We seek the commonly adopted fastening method in such assemblies. Context is conventional Indian/UK-style steel sleeper practice with keys or clips. Concept / Approach: Unlike timber sleepers, which commonly use dog spikes through base plates or directly into wood fibers, steel sleepers are manufactured with upturned lugs or jaws. A key or clip is driven between the rail foot and the lug to clamp the rail securely. This arrangement provides a resilient hold-down while minimizing damage to the sleeper and rail foot, and it is compatible with repeated maintenance cycles. Step-by-Step Solution: Identify sleeper material: steel sleeper with pressed lugs/jaws.Recognize compatible fastening: driven keys or clips into lugs/jaws to lock the rail foot.Exclude timber-only methods such as dog spikes as a primary system for steel seats.Conclude that “keys in lugs or jaws” is the standard practice. Verification / Alternative check: Track standards and manufacturer drawings for pressed steel sleepers consistently show rail seats with lugs and a driven key (or elastic clip) arrangement, confirming this fastening method as the norm. Why Other Options Are Wrong: Dog spikes: Primarily for timber sleepers and not the principal fastener for steel sleeper rail seats.Bearing plates: Plates distribute load on timber; they are not the fastening mechanism on steel sleepers.None of these: Incorrect because a well-known method exists (keys in lugs or jaws). Common Pitfalls: Confusing baseplates (load spreaders) with fastening systems. Assuming timber sleeper practices directly apply to steel sleepers. Final Answer: by keys in lugs or jaws

Question 12

Standard dimensions of a wooden sleeper for Broad Gauge (BG) track In Indian Railways permanent-way practice, what are the commonly adopted standard dimensions for a wooden sleeper used on Broad Gauge track?

Accepted Answer

Introduction / Context: Correct sleeper dimensions ensure adequate bearing area under the rail seat, proper ballast contact, and stable gauge control. For Broad Gauge (BG), standard timber sleeper sizes have evolved from service experience to balance strength, durability, and economy. Given Data / Assumptions: The question refers to widely used, standard dimensions for BG timber sleepers. Dimensions are given as length × width × thickness. Options include sizes used for other gauges as distractors. Concept / Approach: BG requires longer and thicker sleepers than metre gauge or narrow gauge to provide sufficient bearing and stability. A length of about 2.74 m provides good ballast distribution and lateral resistance, while a cross section near 25 cm × 13 cm ensures adequate rail-seat depth and stiffness against bending. Step-by-Step Solution: Recognize BG sleepers are longer than MG/NG sleepers.Compare the listed sizes to common standards: 2.74 m × 25 cm × 13 cm matches BG practice.Other sizes correspond to MG or smaller sections and are not standard for BG. Verification / Alternative check: Code books and maintenance manuals list the BG timber sleeper at approximately 2.74 m length and a suitable cross-section near 25 × 13 cm as a standard reference size for design and procurement. Why Other Options Are Wrong: 1.83 m × 20 cm × 11 cm; 1.52 m × 15 cm × 10 cm: Closer to MG/NG dimensions, not BG.1.75 cm × 20 cm × 12 cm: The length is clearly nonstandard and likely a typographical decoy.None of these: Incorrect because a standard BG size is present. Common Pitfalls: Selecting MG sleeper size for BG due to memorization errors. Ignoring the need for longer length on BG to fit sleeper spacing and ballast shoulder. Final Answer: 2.74 m × 25 cm × 13 cm

Question 13

Standard width of ballast section for Metre Gauge (MG) In Indian Railways, what is the commonly adopted standard width of the ballast section for MG track measured at the formation level?

Accepted Answer

Introduction / Context: The ballast section width (at formation) provides lateral stability, drainage, and proper seating for sleepers. For MG, the required width is lower than BG because of narrower gauge and reduced sleeper size and spacing. Selecting the correct width is essential for track stability and maintenance economy. Given Data / Assumptions: Gauge considered: Metre Gauge (MG). We refer to typical standard practice values used historically on Indian Railways. Width is the overall ballast/formation width supporting the sleeper ends and shoulder. Concept / Approach: MG track uses smaller sleepers and has smaller clearances than BG. A common dimension used historically for MG ballast section width is about 2.30 m, which balances shoulder width for lateral restraint with economic use of ballast. Larger widths like 3.35 m or 3.53 m are characteristic of BG sections and therefore not appropriate for MG. Step-by-Step Solution: Identify that MG has narrower requirements than BG.Compare values: 2.30 m suits MG standards; larger values are BG-oriented.Therefore, select 2.30 m as the standard MG ballast width. Verification / Alternative check: Formation drawings and permanent-way manuals for MG show overall ballast widths around 2.30 m, aligning with shoulder and crib requirements for typical sleeper spacing. Why Other Options Are Wrong: 3.35 m and 3.53 m: Typical for BG or heavy-duty sections, excessive for MG.2.50 m: Larger than common MG practice and not the standard reference dimension.None of these: Incorrect because 2.30 m is standard for MG. Common Pitfalls: Mixing BG and MG dimensions due to memory overlap. Confusing ballast section width with formation width in special cases (e.g., turnouts). Final Answer: 2.30 m

Question 14

Extra ballast on curves and welded rail practice Which of the following statements regarding extra ballast width on curves and welded-rail tracks is correct in permanent-way maintenance practice?

Accepted Answer

Introduction / Context: Curved track experiences higher lateral forces due to curvature and cant deficiency. Welded rails (short or long welded) also demand greater lateral resistance from ballast shoulders to prevent buckling and maintain alignment. Hence, standards prescribe extra ballast widths under specific conditions. Given Data / Assumptions: Curves sharper than specified degrees require extra outer shoulder ballast. Welded rail track (SWR/LWR/CWR) typically needs extra shoulder on both sides. Values such as 7.5 cm or 15 cm are standard augmentation amounts used in practice. Concept / Approach: Additional ballast on the outer shoulder of curves counters lateral drift. For welded rails, providing extra ballast on both shoulders increases track lateral and longitudinal resistance, helping to manage thermal forces. Therefore, each listed prescription serves a valid and documented objective in track stability. Step-by-Step Solution: Check each statement against typical permanent-way guidelines.7.5 cm extra on outer side for SWR and for curves sharper than about 3° is a recognized practice.15 cm extra on each shoulder for welded rails enhances resistance and is commonly specified.Since all are correct, the combined option is right. Verification / Alternative check: Standard ballast profiles and welding manuals provide tabulated extra shoulder requirements for curves and welded sections, confirming these statements in maintenance literature. Why Other Options Are Wrong: Individual options are correct, but “All the above” captures the complete, consolidated practice and is therefore the best choice. Common Pitfalls: Applying only one-side extra ballast on LWR/CWR where both shoulders should be augmented. Ignoring site-specific needs such as weak formation or high speeds requiring more stringent profiles. Final Answer: All the above

Question 15

Definition of hogging at rail joints What is the term for the bending deformation of rail ends at a joint caused by loose packing and loose fish bolts, leading to an upward or misaligned end condition?

Accepted Answer

Introduction / Context: Jointed track suffers from problems concentrated at the joints: impact loading, end batter, and deformation. One specific defect is “hogging,” which reflects a bending of the rail ends resulting from poor support and loose fittings, adversely affecting ride quality and increasing maintenance demands. Given Data / Assumptions: Loose packing under the joint. Loose fish bolts and possibly worn fishplates. Repeated impact from wheel loads. Concept / Approach: At a poorly supported joint, successive wheel impacts cause differential bending of the rail ends. This produces a hogged profile (often an upward or misaligned end) which then increases impact further, creating a vicious cycle of deterioration and rapid end batter unless corrected by packing and tightening the joint. Step-by-Step Solution: Identify the root cause: inadequate joint support and loose fittings.Understand the effect: localized bending of rail ends at the joint.Apply terminology: this deformation is called “hogging.” Verification / Alternative check: Inspection manuals describe hogging at joints along with corrective actions: proper packing, bolt tightening, renewal of fishplates, and sometimes joint welding or conversion to LWR/CWR. Why Other Options Are Wrong: Buckling: Lateral/vertical instability due to thermal or compressive forces in continuous lengths, not localized joint end bending.Creeping: Longitudinal movement of rails, unrelated to joint-end bending shape.None of these: Incorrect because a specific term exists. Common Pitfalls: Confusing hogging with end batter; batter is the mushrooming/damage at the running face, while hogging refers to the bending profile. Ignoring joint packing, which is the first-line remedy to prevent recurrence. Final Answer: hogging

Question 16

Switch type for Bull-Head (BH) stock rails When the stock rails used are Bull-Head (BH) rails seated in chairs, which type of switch is generally provided for the turnout?

Accepted Answer

Introduction / Context: Turnout design must match the rail section and seating system. For Bull-Head rails carried in chairs, the switch and its heel/planing style are chosen to provide proper fit and clearance while maintaining strength at the thin switch tip. Given Data / Assumptions: Stock rails are Bull-Head rails (BH) with chair and key fittings. Conventional chairing and planing practices apply. We seek the common switch type used with BH stock rails. Concept / Approach: BH turnouts traditionally use undercut switches, where the underside of the switch rail is planed so that the head can close against the stock rail while clearing the chair and keys. This planing geometry is compatible with BH chair seats and ensures the required running clearance and flangeway. Step-by-Step Solution: Identify rail form: BH section in chairs with keys.Match with compatible switch design: undercut planing is standard for BH practice.Conclude “undercut” as the generally provided switch type. Verification / Alternative check: Traditional turnout drawings in BH practice specify undercut switch geometry to suit chair spacing and keying; this has been standard for decades in BH territories. Why Other Options Are Wrong: Articulated/over riding/straight cut: These do not reflect the specific planing and seating needs for BH rail in chairs. Common Pitfalls: Confusing BH practices with modern flat-bottom rail turnouts that often use different switch planing and baseplate systems. Final Answer: undercut

Question 17

Location of the outer signal on Broad Gauge (BG) For BG lines, what is the standard distance at which the outer signal is placed from the station limit to provide adequate braking and approach warning?

Accepted Answer

Introduction / Context: Signal placement determines train braking distance, sighting time, and safe approach to stations. The “outer signal” warns drivers before the home signal and is positioned to satisfy both operational needs and safety margins on Broad Gauge routes. Given Data / Assumptions: Gauge: Broad Gauge (BG). Normal approach speeds and typical braking characteristics are assumed. Standardized distances are used to ensure uniform operation. Concept / Approach: The outer signal must be far enough from the station limit to allow a driver to sight the aspect, react, and control the train safely before reaching the home signal. Historical practice on BG has standardized this distance at about 540 m from the station limit, balancing braking needs and signal spacing constraints. Step-by-Step Solution: Identify the function of the outer signal: advance warning prior to home.Consider braking/sighting norms for BG operations.Apply standard distance: about 540 m from station limit on BG. Verification / Alternative check: Operating manuals and signal-siting guidelines list typical distances for BG, with the 540 m placement being a commonly cited standard for outer signals under conventional conditions. Why Other Options Are Wrong: 510–530 m or 550 m: These are not the standard benchmark distances and may not provide the designed uniformity across stations. Common Pitfalls: Confusing outer signal with distant signal placement, which can vary more with speed and gradient. Overlooking site-specific adjustments (curves, gradients) that may require refined placement. Final Answer: 540 m

Question 18

Crossing number from standard BG crossing length If the standard length of a Broad Gauge (BG) common crossing is 597 cm, what is the corresponding “number of crossing” (ratio describing the crossing angle)?

Accepted Answer

Introduction / Context: Turnout geometry uses the “number of crossing,” such as 1 in 8, 1 in 12, or 1 in 16, to express the crossing angle. The standard length of a crossing for a given gauge correlates with this number through turnout layout relationships used in permanent-way design and fabrication. Given Data / Assumptions: Gauge: Broad Gauge (BG). Standard common crossing length: 597 cm. We match this length to a commonly used crossing number. Concept / Approach: For BG, a standard crossing length around 6 m corresponds to a moderate crossing angle. In practice, 597 cm aligns with a 1 in 12 crossing, widely adopted for mainline turnouts due to a balanced compromise between speed and layout length. Step-by-Step Solution: Identify typical BG crossing options: 1 in 8, 1 in 12, 1 in 16.Associate standard lengths: around 6 m length is consistent with 1 in 12 geometry.Hence, the crossing number is 1 in 12. Verification / Alternative check: Turnout tables mapping standard lengths to crossing numbers indicate that ~5.97 m is the reference for 1 in 12 on BG layouts, confirming the selection. Why Other Options Are Wrong: 1 in 16: Generally corresponds to a longer, flatter-angle crossing than 597 cm.“1 in” without a denominator: Incomplete description and not a valid option.None of these: Incorrect because a valid mapping exists. Common Pitfalls: Confusing BG tables with MG/NG data, which have different reference lengths. Assuming a linear relation without considering the specific turnout standard adopted. Final Answer: 1 in 12

Question 19

Minimum gradient in station yards What is the usual limiting steepness for the minimum gradient adopted within station yards to prevent undesired rolling and to simplify shunting?

Accepted Answer

Introduction / Context: Station yards contain many pointwork elements and standing vehicles. Excessive gradients can cause vehicles to roll, complicate shunting, and increase safety risks. Therefore, a gentle limiting gradient is specified for yard design and reconstruction. Given Data / Assumptions: We seek the typical maximum steepness (minimum gradient) used within yards. Operational safety and ease of shunting are priorities. Concept / Approach: Yard gradients are kept as flat as practicable. A commonly adopted limiting gradient is 1 in 400. Flatter gradients like 1 in 1000 are even better but may not always be feasible; steeper than 1 in 400 increases operational risk and complicates stabling and coupling operations. Step-by-Step Solution: Consider safety: minimize uncontrolled movement.Adopt a practical limit: 1 in 400 serves as a standard yard maximum gradient.This value balances drainage/formational needs with operational safety. Verification / Alternative check: Permanent-way and yard-layout guides cite 1 in 400 as a commonly accepted limit for yard gradients under normal conditions, with local adjustments as required. Why Other Options Are Wrong: 1 in 1000 and 1 in 750: Flatter than necessary and not the usual limiting value.1 in 500: Sometimes used, but 1 in 400 is the prevalent limiting standard.Zero: Ideally flat, but impractical over long yards and not codified as a general rule. Common Pitfalls: Assuming the flattest possible gradient is always used; site constraints often dictate the practical limit. Confusing mainline ruling gradients with yard gradient standards. Final Answer: 1 in 400

Question 20

Composite Sleeper Index (CSI) requirement for bridge sleepers For wooden sleepers used over bridge girders, what is the minimum Composite Sleeper Index (CSI) typically specified to ensure adequate strength and durability?

Accepted Answer

Introduction / Context: The Composite Sleeper Index (CSI) is a numerical index that combines key properties of timber (like strength, durability, and resistance to decay) to rate suitability. On bridges, sleepers face concentrated loads, vibration, and exposure; thus, a higher CSI is mandated for safety and longevity. Given Data / Assumptions: Application: timber sleepers over bridge girders. We seek the minimum CSI threshold typically specified. Bridge environments impose more severe loading and exposure than plain track. Concept / Approach: Higher CSI sleepers perform better under repetitive impact and variable moisture conditions prevalent on bridges. A minimum CSI of about 1455 is commonly stipulated to ensure that only high-quality timber species are used for bridge sleeper applications. Step-by-Step Solution: Recognize increased demands on bridge sleepers: impact, limited ballast, exposure.Apply the index threshold commonly used for bridge service.Select CSI ≥ 1455 as the minimum requirement. Verification / Alternative check: Procurement and design guides list higher CSI requirements for bridge sleepers than for ordinary track, with 1455 cited as a typical minimum. Why Other Options Are Wrong: 1355, 1255, 1155: Suitable for lesser-duty applications; inadequate for bridge loading and exposure.None of these: Incorrect because a recognized minimum exists for bridges. Common Pitfalls: Selecting sleepers fit for plain track but not bridge duty, leading to premature failures. Overlooking treatment and seasoning, which also affect long-term performance. Final Answer: 1455

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