The gallery’s opening visible above the five piers of the bridge
As modern trains labour up the gradients of the Bolan Pass en route to Quetta, few travellers on-board would know that the first train to reach that city had not come up this way. In March 1887, the first ever train to reach Quetta had turned north at Sibi, passed through the Nari river gorge to reach the cool heights of Harnai, traversed that dramatic crack of Chappar Rift, veered west to Khanai and thence turned south to Bostan in order to make it to Quetta.
Chappar hill is shaped like a Swiss roll – a convex semicircular structure – at its western end. To the east, it turns into a fat mass of rock, deeply furrowed by rainwater that has washed down its contours for eons. Near the western end, the hill is cut asunder by a gaping chasm — a rift wrought by an earthquake that hit very long ago. At the bottom of the gash flows a stream which, depending on the weather, can either be a foaming torrent or a mere puddle.
The remains of a monitoring station near the southern end of the chasm remind us of the time when officialdom kept close tabs on how much water was making through the stream.
While the verges of the rift are near vertical as if sliced by a surgeon’s lancet, a short way west is a wide furrow descending from its higher northern side to the south. Millenniums before the British conjured the idea of laying a steel road across this magical hill, caravans of traders and seasonal migrants wound their way up and down this furrow. In rainless seasons when the rivulet at the bottom of the rift flowed low, they sloshed along through the chasm too.
And then in the 1880s came the time to connect Quetta with the rest of the fast developing railway network, and surveyors with their theodolites and plane tables scrambled up hills near the rift to figure out the way the steel line would go. Because of its highly fickle flow of water, it was out of the question to lay the line at the bottom of the rift. As for the gentler furrow to the west, the gradient in it was too steep for a train to be hauled up.
The gradient difference between the lower and higher sides was workable only at the southern end of the rift. Here they could take the line around in a wide loop, slowly rising along the hill’s contours. As the line hit the syncline, it was taken into what can hardly be called a tunnel for it does not bore through the heart of the hill. The engineers called it ‘the gallery’.
And a gallery it was — with the entire hill on one side and only a shell of a rock on the other side. The shell, never more than two or three metres thick, had large gapes at regular intervals to let light in and get smoke out. Debris from the excavation can still be seen dribbling down the side of the holes along an ever rising line until the gallery exits into open air high above the valley. On Google Earth at North 30º-20, East 67º-29’, these holes can be seen next to the remains of what was once named the Louise Margaret bridge.
There can be no better description of this section of the railway line than the words of P S A Berridge (the author of Couplings to the Khyber: Story of the North Western Railway): “From this tunnel the line emerged out of the vertical wall of the rift, which it crossed on a bridge of seven 40-foot plate girder spans and one truss span of 155 feet, and then entered the opposite cliff face by another tunnel which, curving around, brought the track parallel with the rift itself.”
As one climbs up to the level of the bridge piers, one cannot but marvel at the mind that thought up this ingenious plan to raise the track up from a height of 1,460 metres near Drigi village at the southern end of the rift, to 1,525 metres at the bridge across the chasm — and eventually to 1,630 metres on the other side of the hill.
The rift was not only the most difficult part of this line, it was also the most spectacular one. The bridge across the rift, a very fine stitch in the geological tear, was the showpiece of North Western Railway, as the predecessor of Pakistan Railway was then called. Just after its completion in March 1887, Louise Margaret, the Duchess of Connaught, came inspecting and it was named after her.
For 55 years trains steamed up through the Nari gorge, went past Khost and moved into the rift to swing south-west for Quetta. I can imagine how the woof-chug of those powerful superheated steam engines used on this line would have transformed from the closed booming sound in the gallery to hollow reverberation over the Louise Margaret bridge as the clatter echoed off the gorge walls and its distant floor some 70 metres below. If only I had lived at that time to experience this journey once. Even once would have been enough.
There were difficulties in laying the line from the very beginning. For starters, the station of Mud Gorge was situated right under a clayey hill north of the rift. Every fall of rain would loosen an avalanche of dark, gooey mud that swept down and covered the line. Since this mud quickly hardened, it was necessary to remove it immediately. Because this was a constant irritant, a railway wit renamed the station to Mud Gorge. Luckily for those responsible for the task in those far off days, this line had only one up and down train service per week to Quetta.
Then there were frequent washouts in the scree slopes on the higher side of the rift, so the order was for the line to be inspected every morning for which a team of gangmen was always at hand. On the night of July 11, 1942, an unprecedented fall of rain brought water cascading down the slopes of the rift. Gangmen sent out the following morning to inspect the line found, in Berridge’s words, “the rails hanging in a festoon over a 90-foot gap in the embankment”.
Railway engineers, meanwhile, were hard at work in the Bolan Pass to push a direct line through to Quetta. (That is another tale, and no less heroic than any other North Western Railway story.) The Bolan Pass line was already operational by the summer of 1942, putting Quetta in direct connection with the rest of the railway network in British India. The damage in the rift did not inconvenience anyone so, while the staff remained on the section, there was no move to repair the line. In May 1943, the British government decided to permanently shut down the stretch between Zardalu (near Khost) and Khanai (on the Zhob Valley Railway). World War II was also on and Britain needed all the steel it could get. And so the dismantling of the line began within the year of the decision to close down the section.