Darjeeling Himalayan Railway (DHR) Engine (part 3)
History by Tony Phillips
Soon after Rungtong station the line turns nearly south on to a long spur where another spiral is encountered. This spiral begins just before the fourteenth mile-post, and is one of the most complicated and interesting pieces of engineering on the railway. From Rungtong the line has to ascend to Tindharia station (2,822 ft.) in less than eight miles, the average gradient for this section being a little over 1 in 28. To overcome a sudden rise of 137 ft., there is practically a double loop, the outstanding feature of which is a sharp curvature introduced to fit the alignment to the situation. This second loop is a fine feat of engineering as can be seen in the photo below:
The track, now returning northwards and eastwards for a short distance, runs along the old road, but gradually passes below it, until the third loop is reached at the sixteenth mile-post. Fine views are afforded of the valley below, the Bhutan Range to the east, and the adjacent hills and valleys. In the plains to the south-east can be seen the Teesta River, with an island called Tiger Island, because three tigers were once. shot during one "beat“ there. The river has its source in the Tibetan Lake Chalamu, which is 17,000 ft. above sea-level, and about seventy-four miles north-east of Darjeeling.
At the eighteenth mile the country presented such difficulties that a spiral was impracticable, and a reverse had to be adopted. At an altitude of 2,438 ft., the line, climbing at 1 in 28, enters a curve of 800 ft. radius, followed by one of 400 ft. radius, and reaches a dead-end at 2,473 ft. It then backs up a second leg, rising at 1 in 33 round curves of 400 ft. and 200 ft. radius respectively, to a second dead-end at 2,501 ft. Another climb at 1 in 28 round a curve of 400 ft. radius brings the train to 2,536 ft., so that by means of the reverse or zigzag a total vertical lift of 98 ft. is accomplished.