Gauges & Tracks — Set 2

Correct Answer: D. Connecting two rails

• **Fishplate (connects two rails)** = A fishplate, also called a splice bar or joint bar, is a flat metal bar bolted through holes drilled in the webs of two adjoining rail ends. It holds the two rail ends in alignment both horizontally and vertically, maintaining a continuous running surface and preventing the ends from splaying, sagging, or rising under wheel loads. • **Thermal expansion gap** — Traditional fishplated joints include a small gap (typically 6 mm) between rail ends to allow the steel to expand in summer heat; without this gap, the rails would buckle. In Long Welded Rail (LWR) track, fishplates are replaced by continuous welding and the gap is managed by stress-relief techniques during installation. • Indian Railways is progressively converting fishplated track to LWR/CWR (Continuous Welded Rail), which eliminates the familiar 'clickety-clack' sound, reduces rail-end wear, and allows safe speeds up to 160 km/h and beyond. • 💡 Option A (Holding the sleeper) is wrong because sleepers are held by separate fasteners — elastic rail clips and dog spikes — not by fishplates; Option B (Anchoring the ballast) is wrong because ballast is held by its own weight and the interlocking of angular stone particles; Option C (Providing electricity) is wrong because traction power is supplied via overhead catenary wire or a third rail, not through the fishplate connection.

Correct Answer: D. Punjab

• **Punjab** = Punjab has the highest railway track density per unit area in India, with approximately 45 km of track per 1,000 sq km of geographical area. This is driven by the state's flat alluvial terrain (no elevation barriers to construction), its role as India's grain basket requiring heavy freight movement, and dense inter-city passenger demand. • **British-era legacy** — Punjab's rail grid was intensively developed during British rule to facilitate grain export and military logistics toward the north-west frontier, creating an exceptionally dense network of lines that persists and is reinforced to this day. • The Ambala, Ferozepur, and Firozpur divisions of Northern Railway pass through Punjab, connecting it to Delhi, Jammu, and Rajasthan with high-frequency services. • 💡 Option A (Maharashtra) is wrong because Maharashtra has a large network in absolute length but complex terrain including the Western Ghats that prevents a uniformly dense track grid; Option B (Uttar Pradesh) is wrong because UP has an extensive but more spread-out network resulting in a lower density ratio per sq km; Option C (West Bengal) is wrong because West Bengal ranks high due to the Kolkata metropolitan hub, but Punjab's flat geography gives it a consistently higher track density ratio.

Correct Answer: A. Light Narrow Gauge (0.610 m)

• **Light Narrow Gauge (0.610 m)** = The 610 mm (2-foot) gauge is the narrowest track used in the Indian Railways system. It is currently operated on the Matheran Hill Railway in Maharashtra — a 21 km route from Neral to Matheran that navigates extremely sharp curves with a minimum radius of just 15 metres, possible only because of the tiny 610 mm track width. • **Matheran Hill Railway** — Built in 1907 by Sir Adamjee Peerbhoy, the Matheran line is one of the last 2-foot gauge railways still operating in India. Since no motor vehicles are permitted in Matheran, this little railway is the sole public transport access to the hill station. • The Darjeeling Himalayan Railway also uses 610 mm gauge and is a UNESCO World Heritage Site (1999); both lines are protected as heritage railways under Indian Railways. • 💡 Option B (Meter Gauge) is wrong because Meter Gauge measures 1000 mm, which is far wider than the 610 mm Light Narrow Gauge; Option C (Standard Gauge) is wrong because Standard Gauge measures 1435 mm and is used in urban metro systems; Option D (Broad Gauge) is wrong because Broad Gauge at 1676 mm is the widest gauge on Indian Railways and is the opposite of the narrowest.

Correct Answer: D. Perpendicular

• **Perpendicular placement** = Sleepers are laid at right angles (90°) to the direction of the rails so that each sleeper bridges across both rails simultaneously. This perpendicular orientation locks the two rails at the correct gauge distance and resists the lateral forces of passing wheel flanges that would otherwise push the rails apart or allow them to close inward. • **Load distribution** — A sleeper's primary structural function is to receive the concentrated rail load at the rail seat and spread it as a distributed pressure over the ballast surface below. PSC sleepers on Broad Gauge are 2.75 m long and weigh about 320 kg, providing a large bearing area on the ballast. • Sleeper density on Indian Broad Gauge main lines is 1,540 sleepers per km, which determines how effectively the concentrated wheel load is distributed to avoid excessive ballast and subgrade stress. • 💡 Option A (Parallel) is wrong because sleepers running parallel to the rails would provide no cross-bracing whatsoever and the two rails would quickly spread apart under wheel loads; Option B (Circular) is wrong because circular placement has no structural meaning in railway track geometry; Option C (At 45 degrees) is wrong because diagonal placement would be structurally inefficient, would not uniformly support both rails, and would make it impossible to maintain a consistent gauge.

Correct Answer: A. RDSO

• **RDSO (Research Designs and Standards Organisation)** = RDSO, headquartered in Lucknow, is the sole technical advisory and standard-setting body of Indian Railways. It develops specifications for tracks, gauges, rolling stock, bridges, signalling, and all railway infrastructure components. It was established in 1957 by merging the Railway Testing and Research Centre (Lucknow) with the Central Standards Office. • **Certification authority** — No new rail profile, sleeper design, fastening system, or bridge component can be procured or deployed on Indian Railways without obtaining RDSO's design approval and drawing number. RDSO inspects prototypes, conducts field trials, and issues mandatory technical circulars. • RDSO publishes the Indian Railway Standard Open Line Drawings (IRSOD), the Track Machine Manual, and the Bridge Rules — the definitive technical references for all IR engineers, contractors, and suppliers. • 💡 Option B (ISRO) is wrong because ISRO (Indian Space Research Organisation) is responsible for space missions and satellite technology and has no mandate over railway engineering standards; Option C (NITI Aayog) is wrong because NITI Aayog is a government policy and strategy think tank with no technical standards authority over rail infrastructure; Option D (NHAI) is wrong because NHAI (National Highways Authority of India) manages highway construction and has no jurisdiction over railway tracks or gauges.

Correct Answer: D. Reduce maintenance and joints

• **Long Welded Rails (LWR)** = LWR consists of individual rail sections welded end-to-end into continuous lengths of 250 m or more, drastically reducing the number of fishplated joints which are the weakest, most maintenance-intensive points on any track. Fewer joints mean less rail-end wear, reduced ballast disturbance, and a much smoother ride for passengers. • **Speed and noise benefit** — The elimination of joints removes the repetitive impact loads that cause the 'clickety-clack' sound; LWR allows Broad Gauge tracks to be passed at speeds up to 160 km/h safely, compared to about 120 km/h on heavily-jointed track. • Indian Railways has converted over 80% of its Broad Gauge main-line track to LWR/CWR (Continuous Welded Rail) as of 2024, and aims for 100% on all Group A routes. • 💡 Option A (Increase noise) is wrong because LWR does exactly the opposite — it reduces noise by eliminating the rail-joint impact that causes the clicking sound; Option B (Save steel) is wrong because LWR uses the same amount of steel as jointed track; the rails are welded, not reduced; Option C (Slow down trains) is wrong because LWR actually enables higher safe speeds by providing a smoother, jointless running surface.

Correct Answer: A. The final track structure

• **Permanent Way** = The term 'Permanent Way' encompasses the complete assembled track structure: rails, sleepers (ties), fishplates or welds, fastening systems, ballast, and the prepared subgrade beneath. It is the finished, operational trackwork that a train runs on, as distinguished from temporary tracks laid during construction of earthworks or bridges. • **Origin of the name** — The term dates to the early 19th century in Britain, when contractors first laid 'temporary ways' (light tracks for construction wagons) and then removed them to install the 'permanent way' for regular train operation. The phrase entered standard railway engineering vocabulary worldwide. • Maintaining the Permanent Way — keeping correct gauge, level, alignment, and surface — is the core responsibility of the Permanent Way Inspector (PWI) at each section, who patrols tracks regularly and schedules tamping, lifting, and slewing operations. • 💡 Option B (The railway station) is wrong because a railway station is a passenger/freight facility building and platform, not the track itself; Option C (The administrative office) is wrong because administrative offices are the headquarters of railway divisions and zones, unrelated to track infrastructure; Option D (A non-stop train) is wrong because 'non-stop' describes a train service pattern and has nothing to do with track structure terminology.

Correct Answer: D. Cant or Super-elevation

• **Cant (Super-elevation)** = On curved tracks, the outer rail is raised above the inner rail by a carefully calculated height called the cant or super-elevation. This tilts the entire train slightly inward, so that the component of gravity acting on the train counteracts the centrifugal force trying to push it outward, allowing the train to traverse the curve safely at speed. • **Design formula** — The equilibrium cant is calculated as e = GV²/127R (where G = gauge, V = speed in km/h, R = radius in metres). On Indian Broad Gauge main lines, the maximum permitted cant is 165 mm, with an additional 75 mm of cant deficiency allowed for faster trains. • Transition curves (spiral or clothoid curves) are provided at each end of a circular curve so that super-elevation is introduced and removed gradually, preventing sudden jerks to passengers. • 💡 Option A (Camber) is wrong because camber is a slight convex upward curve given to the top of a rail head or road surface for drainage, not the lateral tilt of one rail above the other; Option B (Gauge widening) is wrong because gauge widening refers to intentionally increasing the track gauge slightly on sharp curves to allow wheel flange clearance, not tilting the rails; Option C (Gradient) is wrong because gradient is the longitudinal rise or fall of the track along its length, measured as a ratio or percentage, not the lateral height difference between rails.

Correct Answer: C. Flat footed

• **Flat-footed (Vignole) rail** = The flat-footed rail has a wide, flat base (foot) that sits directly on the sleeper without any intermediate chair. This design distributes the load over the entire foot area, provides excellent stability against overturning, and is simple to fasten using clips, spikes, or bolts. It is the universally adopted rail section on all modern railways including Indian Broad Gauge. • **Current standard** — Indian Railways uses 60 kg/m and 52 kg/m flat-footed rails on Broad Gauge main lines and branch lines respectively. The 60 kg/m rail is now specified for all new track laid on high-density routes, with a service life of 30–40 years under heavy traffic. • The flat-footed section replaced the bull-headed rail (which needed a cast-iron chair to grip the sleeper) on Indian main lines during the 20th century, as the simpler flat-foot design proved more economical and reliable. • 💡 Option A (Double headed) is wrong because double-headed rails had identical top and bottom profiles (intended to be turned upside down when worn), but the idea failed in practice as the bottom surface became grooved and was abandoned in the 19th century; Option B (Bull headed) is wrong because bull-headed rails, which need separate cast-iron chairs to grip the sleeper, are now obsolete on Indian Railways and survive only on a few heritage lines; Option D (V-shaped) is wrong because no standard railway rail has a V-shaped cross-section; this is not a recognised rail profile used in any railway system.

Correct Answer: A. Expansion joints

• **Expansion joints** = Steel rails expand when temperature rises and contract when it falls, at a rate of about 0.012 mm per metre per degree Celsius. Expansion joints — short rail sections with oblique cuts and fishplated joints — provide the controlled gap needed to accommodate this thermal movement without allowing the track to buckle in summer or develop dangerous gaps in winter. • **Temperature range** — On Indian Broad Gauge, a 13-metre rail can expand by up to 15 mm over a 100°C temperature range (from winter night to summer day in Rajasthan). Without managed gaps, the compressive force would cause the track to buckle sideways — a phenomenon called 'sun kink' — leading to derailments. • In Long Welded Rail (LWR) track, expansion joints are replaced by Glued Insulated Rail Joints (GIRJ) or Breathing Lengths at the ends of each welded panel, where controlled thermal movement is allowed within defined limits. • 💡 Option B (Sleepers) is wrong because sleepers provide rigid support to the rails and do not accommodate longitudinal thermal movement; Option C (Ballast) is wrong because ballast provides vertical and lateral restraint to sleepers but cannot control rail expansion gaps; Option D (Fasteners) is wrong because rail fasteners like elastic clips hold the rail down to the sleeper but do not create or control the longitudinal gap needed for thermal expansion.