Track gauge in India

Tracks of the smallest and broadest gauge next to each other in New Jalpaiguri Station

Comparison of different gauges common in India with the standard gauge, which is not common in India

Railway track gauge in India is complicated by historical usage of multiple track gauges.

Indian Railways uses four gauges:

• 1,676 mm (5 ft 6 in) Broad Gauge (BG), which is also called Indian gauge,
• 1,000 mm (3 ft 3 ³⁄₈ in) metre gauge (MG),
• 762 mm (2 ft 6 in) Narrow Gauge (NG), and
• 610 mm (2 ft) Narrow Gauge.

Project Unigauge that started in 1991 seeks to standardise the rail gauges in India by converting most of the MG and NG tracks to BG track. Some NG tracks on which heritage trains run in hilly regions to Shimla, Darjeeling, Ooty, Kangra will not be converted.

Delhi Metro Rail Corporation constructed 1,435 mm (4 ft 8 ¹⁄₂ in) Standard Gauge (SG) in Delhi in 2010 and runs metro trains on 42 km (26 mi) of standard gauge in 2014. However, Delhi Metro is a separate urban mass rapid transit system not owned by Indian Railways.

Overview

Broad Gauge is the most widely used rail gauge in India with approximately 108,000 km (67,000 mi) of track length and 60,000 km (37,282 mi) of route length in 2014. In some regions, Metre Gauge is common for historical reasons and consists of about 4,000 km (2,485 mi) of route length, down from more than 20,000 km (12,427 mi) in late 1970s. Narrow gauges are present on a few routes lying in hilly terrains and in some private railways because of cost considerations. Narrow gauges covered less than 2,000 km (1,243 mi) route length in 2014.

Among the notable Mountain Railways of India, the Nilgiri Mountain Railway uses Metre Gauge whereas the Darjeeling Himalayan Railway, the Kalka-Shimla Railway, the Kangra Valley Railway, and the Matheran Hill Railway use Narrow Gauge.

Broad Gauge

The Governor-General of India in the 1850s chose BG for India rather than the SG. The two main reasons given were greater stability during periods of high wind and unpredictable weather and greater space between the wheels for bigger inside cylinders (although this ceased to be a problem when outside cylinders were introduced).

The inability to source standard equipment was not seen to be a problem or was overlooked. The extra cost of longer sleepers was not considered to be a problem, though later the cost saving of shorter sleepers with MG was considered to be an advantage.

Standard Gauge

Small lengths of standard gauge (1435 mm) have existed in India for individual projects and short line lengths. Until 2010, the only standard gauge line in India was the Kolkata (Calcutta) tram system.

In 2010 Delhi Metro Rail Corporation started metro train on standard gauge track on Mundka-Inderlok-Kirti Nagar sections and on Central Secretariat-Badarpur sections. The Green Line, Violet Line, and the Delhi Airport Metro Express operate on standard gauge. More standard gauge tracks will become operational in 2015.

Furthermore, the Rapid MetroRail Gurgaon, the Bangalore Metro and the Mumbai Metro also operate on standard gauge. Most new metro systems planned to be built in India will use standard gauge, as it is easier to acquire rolling stock for standard gauge than for Indian gauge. All of these will be operated separately from Indian Railways, which does not operate any track on standard gauge.

Metre Gauge

In the 1880s, when the BG tracks had been laid over some routes, another Governor-General considered the introduction of infill 1,000 mm (3 ft 3 ³⁄₈ in) metre gauge MG lines to reduce the cost.

Narrow Gauge

Main article: Narrow gauge railways in India

Narrow gauges are present on a few routes lying in hilly terrains and in some private railways because of cost considerations. Narrow gauges covered a total of 2,400 km (1,491 mi) route length in 2011. NG railway tracks were constructed for cost considerations, and because simpler engineering permitting sharp turns in hilly regions. The argument was that if money could be saved building MG, then presumably more money could be saved by building NG. The design process during construction was taken to its extreme, with the gauge being carefully chosen to optimise costs for the traffic offering. The result being that each line might be a different gauge, even if it would have been more useful to have a through service.