Govt. Exams
Entrance Exams
# Sleeper Density in Indian Railways
The sleeper density for railway tracks refers to the number of sleepers (cross-ties) required per rail length unit, expressed as \(M + x\), where \(M\) is the rail length in meters.
Step 1: Understanding Sleeper Density Formula
In Indian railways, the standard sleeper density formula is:
where \(M\) is the rail length in meters and \(c\) is a constant that varies by track type.
Step 2: Classification by Track Type
Different track categories have different density requirements:
- Main tracks (broad gauge): Higher density for better stability and load distribution
- Branch lines and sidings: Lower density due to reduced traffic
- Curves and steep grades: Higher density for structural integrity
Step 3: Main Track Standard in India
For main tracks in Indian railways (broad gauge standard), the sleeper density is standardized to provide adequate support under heavy and frequent traffic loads:
This means for a rail length of \(M\) meters, approximately \(M + 4\) to \(M + 7\) sleepers are placed. For example, if \(M = 12.8\) meters, then 16.8 to 19.8 sleepers per rail would be used.
Step 4: Verification Against Options
- Option (A): \(M + 4\) to \(M + 7\) ✓ Matches main track standard
- Option (B): \(M + 2\) to \(M + 4\) — Too sparse for main lines
- Option (C): \(M + 5\) to \(M + 10\) — Higher density (branch/sidings)
- Option (D): \(M + 3\) to \(M + 6\) — Intermediate density
Answer: \(M + 4\) to \(M + 7\) sleepers per rail length (Option A)
A fish plate is a steel plate used to connect two rail sections by bolting them together at the joint.
CRIS (Central Rail Information System) is the IT backbone of Indian Railways, managing reservation and ticketing systems.
If BG:MG = 4:1 and BG = 80,000 km, then MG = 20,000 km. Total = 80,000 + 20,000 = 100,000 km.
# Railway Zones in India — Coverage Analysis
To answer this question, we need to identify which railway zone operates across the most number of states in India.
Step 1: Identify the Northeast Frontier Railway (NFR) coverage
The Northeast Frontier Railway is headquartered in Guwahati and operates across the northeastern states of India. It covers:
- Assam, Arunachal Pradesh, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim, and Tripura
This gives a total of 8 states.
Step 2: Compare with other major zones
- Central Railway: Covers Maharashtra, Madhya Pradesh, Chhattisgarh, and Telangana (approximately 4 states)
- Western Railway: Covers Gujarat, Rajasthan, Maharashtra, and Goa (approximately 4 states)
- South Eastern Railway: Covers Jharkhand, Odisha, West Bengal, and Bihar (approximately 4 states)
Step 3: Verify the maximum coverage
The Northeast Frontier Railway clearly operates across the maximum number of states (8 states) compared to the other listed zones, which each cover only about 4 states.
Answer: The Northeast Frontier Railway (NFR) covers the maximum number of states in India with 8 states in the northeast region. (Option D)
Remaining time = 6 - 2 = 4 hours. New speed required = 360/4 = 90 km/h.
Welded joints (including Continuous Welded Rail or CWR) are preferred in modern railways as they reduce vibration and wear.
Grade crossing gates control road traffic at level crossings to ensure safety when trains pass through.
This is a factual question about Indian railway infrastructure standards. The standard thickness of rail in the Indian broad gauge system is a fixed specification established by Indian Railways.
Step 1: Understand Broad Gauge Specifications
Indian Railways uses three gauge types: broad gauge (1676 mm), meter gauge (1000 mm), and narrow gauge (762 mm). The broad gauge is the primary network. Rail thickness is a standardized dimension for structural integrity and load-bearing capacity.
Step 2: Identify Rail Thickness Standard
The standard thickness of rail in the Indian broad gauge system is established by the Indian Railway Standards (IRS). This specification ensures uniform quality, durability, and safe operation across all broad gauge tracks.
Step 3: Eliminate Incorrect Options
- Option (B) 90 mm — too thin for broad gauge rails
- Option (C) 100 mm — close but not the standard specification
- Option (D) 110 mm — exceeds the standard thickness
- Option (A) 15.5 mm — correct standard specification
Step 4: Confirm the Answer
The Indian Railways broad gauge system uses rails with a standard thickness of 15.5 mm. This specification has been maintained across the entire broad gauge network to ensure consistency and safety.
Answer: 15.5 mm (Option A)
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Note for students: This is a factual recall question commonly asked in RRB/NTPC exams. Memorize that Indian broad gauge rail thickness = 15.5 mm. Other related standards: rail head width ≈ 67 mm, rail foot width ≈ 90 mm.
Eastern Railway has its headquarters in Kolkata (formerly Calcutta), one of the oldest railway zones in India.
