Curves :
The curves are necessarily very sharp on account of the contour of the moutains, no tunnels being bored, a fact for which the traveller in the interests of his comfort and of the scenic pleasures of the journey may be grateful. The sharpest curve on the line is at Loop No. 4 mile 21 and has a radius of 59 feet.

Engines:
The standard engines have four coupled wheels and weigh 14 tons; the cylinders being 2 inches bore and 14 inches stroke. A Garrat, or eight-wheeled articulated engine weighing 28 tons, is also in use in the hill station, while a Pacific type engine with bogie tender is in use in the plains section. This last named engine weighs, with tender, 49 tons.

Rolling Stock:
The ordinary passenger bogies in use have a body 24 feet 3 inches long and are 26 feet 6 inches over all. Bogie vans and trucks are also in use, the longest bogie truck being 32 feet. Rails : The steel rails used in the track weigh 41 1/4 lbs per yard, and portions of the line had been relaid with 50 lb rails.

Gradient:
The steepest gradient on the hill section is 1 in 20, the average gradient is 1 in 29. The line from Sukna to Ghoom rises in one continuous grade, there being no reverse or counter grades in a distance of 40 miles.

Cost:
The original cost of the 51 miles of railway from Siliguri to Darjeeling was Rs. 17,50,000 but improvements made during subsequent years have brought the cost up to Rs. 43,00,000 in the year 1920



Quick Reference:
Number of curves - 919(74%)
Ruling gradient - 1 in 29 (steepest 1 in 18)
Steepest curve - 100 degrees (one of 120 degrees)
Number of bridges - 556 (241 corbelled arch)
Number of level crossings - 177 (4 manned)
Rails - 50lbs
Ballast - 75mm (earth = cinder)
Points of crossings - 1 in 5, 1 in 8.5
Speed on turn out - 8kph
Rolling stock - 14 Locos., 38 carriages
Staff - Civil 309, Mechanical 562, Commercial 66, Electrical 51
Loop 1 - 299 metres, Loop 2 - 172 metres, Loop 3 - 549 metres.