Da Lat Cog Railway

Between the two ordinary rails runs a third rail. Along its whole length is a row of steel teeth, perfectly even and packed close, like the teeth of a giant iron comb. Lay a hand on it and the steel feels cold and rough. Those teeth are not there to cut. They are there to grip. A whole railway was born because of them.

The problem came down to two numbers. At Tháp Chàm, on the coast side, the track sits 32 meters above sea level. At Da Lat, up on the plateau, it sits at 1,488 meters. Between those two numbers is a climb of more than 1,400 meters, and the train has to haul itself up all of it. The track that joins the two ends runs 84 kilometers. Across the middle stand two steep mountain passes, the Ngoạn Mục Pass and the Đran Pass.

Iron wheels on iron rails have very little grip. On level ground, that is a strength. But the average grade here is 12 percent. That means that over the length of a soccer field, the train has to climb as high as a four-story house. On a slope like that, iron wheels can only spin in place. They need something to grip, and the row of steel teeth in the middle is exactly that.

The teeth run about 16 kilometers in all, but not in one piece. They are split into three stretches, all on the hardest leg, from Krông Pha up to Da Lat. Today Krông Pha is usually called Sông Pha. Three times the mountain rose straight up, and three times the builders set teeth down the middle. From Krông Pha up to Eo Gió. From Đran up to Trạm Hành. From Đa Thọ on to Trại Mát.

Laying that railway across the mountains took 24 years. The French began work in 1908. Only in 1932 did trains run the whole way through. First came the stretch from Tháp Chàm to Xóm Gòn. The next stretch, on to Sông Pha, was finished in 1917. The hardest leg, from Sông Pha up to Da Lat, took ten long years of work from 1922. A child born when the first picks struck the ground was grown up by the day the trains ran the full line.

Where the mountain would not give way, the builders had to go through it. Along the line, workers cut five tunnels into the rock. Each tunnel is 6.6 meters high, about the height of a two-story house. Each is 4.6 meters wide, just enough for a train to squeeze through. Some tunnels sit right on the Ngoạn Mục Pass, carved straight into the cliff. The train slips inside, the rock presses close to both sides of the cars, and darkness falls for a while.

Where the mountain dropped away underfoot, they had to build bridges. There were 46 of them, standing on hundreds of stone piers. Seen from above, the line was a single iron thread strung across one ravine after another, with a station roof every so often. More than ten stations stood along the way, from the coast up to the plateau.

A railway with teeth needed locomotives that could bite. These climbing machines came from a works in Winterthur, in Switzerland. The rack system used here is named after a Swiss engineer, Roman Abt. Under each engine's belly sat a set of cogwheels, quite separate from the ordinary wheels. Starting in 1923, nine larger engines were built just for the steep leg from Sông Pha up to Da Lat.

Near the foot of a slope, the driver slowed the train right down. The cogwheels under the engine eased into mesh with the teeth in the middle. From that moment, the train no longer rolled. It crawled. The cogs bit into the rail teeth one notch at a time, inching the whole train up toward the plateau. Each notch made a sound, steady and slow, all the way up the slope. Going downhill, the same teeth held the train back and kept it from sliding away.

There was one more engine, bearing the number one. It left the works in 1913, and for several decades after that it climbed only Swiss mountains. Then the mountain line back home switched to electric power. The steam engine was out of work. In 1947 it was sold to French Indochina, and it was given a new mountain. It ran 43 kilometers, from Sông Pha up to Da Lat. Up it climbed, then crawled back down, day after day, on a plateau half a world away from home.

Then the railway fell silent. In the war years the trains grew fewer and fewer, then stopped altogether. After 1975, rails, ties, cars and engines were taken away one by one, to serve other lines. The row of steel teeth vanished from the mountainside. In many places only the bare, stony roadbed was left.

But the engines that could bite were not so easily lost. In Switzerland, people who worked on steam railways looked for a way to buy them back. In 1988, a plan to bring them home took shape. In 1990, Vietnam's railways handed over six rack locomotives, and they set off for Switzerland.

Engine number one spent two years in the Meiningen works. It was taken apart piece by piece. It was cleaned, repaired, given new parts, then put back together. On June 9, 1993, it was welcomed back onto the Furka mountain line. It was 80 years old, and it was climbing again.

The Furka line runs only from June to October. It pulls vintage cars up to a height of 2,160 meters. That is nearly 700 meters higher than the station at Da Lat. More than 7,000 volunteers from Switzerland, the Netherlands, Belgium and Germany helped bring that line back. Some of the engines that once climbed the passes to Da Lat now run there. They bite into the row of steel teeth and crawl upward.

In Vietnam, traces of the old line remain. At Phan Rang, a bridge over the Cái River still stands. It is the Tân Mỹ Bridge, though people around it know it as cầu Đen, the Black Bridge. Sông Pha station and the warehouses in Gòn hamlet are now covered in moss. Many other old stations still keep their reinforced concrete frames. The tunnels through the Ngoạn Mục Pass are also still whole. Some are so short that from one end, daylight already shows at the other. The roadbed and the bridge abutments still lie there. But the rails have nearly all been taken away, the toothed middle rail too.

And one stretch has come back to life. In 1991, rails were laid again on the short run from Da Lat out to Trại Mát. The part that still carries passengers today is 6.7 kilometers long. The train stops at Trại Mát, right where the third toothed stretch used to end. A diesel engine pulls four cars, and the ride takes about half an hour. It is slow enough to take in a flower garden, a rooftop, a stretch of mountain town drifting past the window.

On the platform at Da Lat today, an old steam engine stands still, beside a length of rack rail. The steel teeth are still perfectly even, still cold and rough under the hand. Nothing bites into them anymore. But every year, when the train season in Switzerland opens again, the cogwheels of engine number one mesh with that same kind of steel teeth, and a train crawls upward once more. And the length of rail on this platform still lies there, its teeth pointing straight up at the plateau sky, waiting.