22 April 2010

The mystery of the runaway train

Several times a week Rovos Rail trains pass our house, and my wife noticed one passing yesterday morning that was unusual in that it was hauled by a diesel or electric locomotive rather than a steam locomotive. A few hours later we heard that one had been derailed at Pretoria atation, and that some people had been killed and many others injured.

Runaway train: Warning screams futile: News24: South Africa: News:
The traumatised owner of the Rovos Rail train which derailed just outside Pretoria said on Wednesday he screamed at others to jump - but his warnings came too late.

'I screamed at the others (the passengers and crew) to tell them to jump off,' Ruhan Vos said of the train which sped out of control for about 10km from the Centurion station in the direction of Pretoria.

'I jumped off while it was moving.'

Vos said the train stopped in Centurion where tourists were allowed to look at the steam locomotive which would take them to the Capital Park station.

The Rovos Rail trains use vintage rolling stock that has been gutted to transform the coaches into luxury accommodation, and they are very expensive to travel on. We've often said that if we inherited or won a lot of money we'd like to travel on one of them to Dar-es-Salaam (the news story reference to Cape-to-Cairo trips is nonsense -- there is no continuous rail link, and if you want to travel by train north of Dar-es-Salaam there is a break of gauge. Cape Town to Dar-es-Salaam is 1067 mm while north of that it is 1000 mm).

The mystery is why the coaches should run away.

In 1955 I travelled by train on a school trip to Cape Town. We travelled from Johannesburg to Cape Town on the Trans-Karroo in the spring, and woke up in the Karroo to see flowers stretching to the horizon. At Touws Ricver the engine was changed from steam to electric, and we descended into the Hex River Valley, and some of the mountain peaks had snow on them -- the first time in my life I had ever seen snow.

On the return journey ten days later I stood gazing out of the window as we passed through the Hex River valley, gazing at the amazingly beautiful mountains lit by the afternoon sun. Then the scenery became less interesting as the train began the steep climb out of the valley, so I went back to my compartment. We had climbed about halfway out of the valley when the train stopped with an almighty jerk, and we were almost thrown out of our seats. When it hadn't moved for a few minutes we looked out to see what was happening, and there was a small crowd around the electric engines -- two of them in tandem to pull the train out of the valley.

We got out and went forward to have a look. The coupling on the front coach, a heavy cast-iron affair, had broken.

The coach was equipped with an emergency coupling -- a piece of chain -- which the crew hooked on to the engine. But before the train could go again, the vacuum brake pipe had to be repaired. When the coupling broke, the brake pipe stretched and broke too, and the jerk we had felt was caused when the air rushed into the broken pipe to fill the vacuum, and the brakes were suddenly applied.

The train crew cut the broken pipe with a penkife, and mended the break with insulation tape. When it was done, we all got back into the train, and it started forward again, but hadn't gone more than a few feet when it rolled back, and stopped with another jerk. We got out and went to see what had happened. The chain had broken. Not surprising, since it had to carry the whole weight of the train. Since it had broken while the train was just pulling away, it rolled back a few feet before the vacuum pipe broke, and was brought to a sudden halt as the brakes were applied.

The crew got to work again. There were enough links left in the chain to reach the rear engine -- just. There was enough vacuum pipe left to join it up again, but stretched out, and no longer in a loop. If it broke again we would be stranded on the mountainside, and since it was a single line at that point, the main line between Johannesburg and Cape Town would be blocked. We got back in the train, and the crew pulled away very carefully, and this time the link did not break, and we made it to Touws River, where the heavy coupling on the front coach was replaced, and the vacuum brake pipes replaced as well. The steam engine was put on -- a massive one with a condensing tender to conserve water in the run across the dry Karroo. It was night by then, and the train was late.

The point of the story is that most of the coaches on the train in 1955 in regular service were the same vintage as those in the Rovos Rail trains. The front one, where the coupling broke, was the oldest, built in the 1920s. The others had probably been built in the 1930s and 1940s. They are the same as the ones that have been converted into luxury accommodation for Rovos Rail. The coach we travelled in was second class, with six compartments with six sleeping bunks in each, and two coupés with three bunks in each. Rovos Rail just stripped out the compartments and made them into bigger and posher bedrooms. But surely they left the vacuum braking system intact. The track out of the Hex River valley is steeper than that between Centurion and Pretoria, and when the coupling broke the train did not run away to the bottom. The second time it did roll back a few feet, but the moment the vacuum pipe broke it stopped with a vicious jerk.

So how could similarly equipped coaches on the Rovos Rail train run away down a hill that is not as steep? As soon as the vacuum pipe was uncoupled from the engine the brakes should have been applied throughout the train.

So therein lies a mystery.


Tauratinswe said...

My bet is that the brake system wasn't connected. That's the way things work in this world these days.

James Higham said...

Mystery indeed. Seems like old stock is a big factor in these things.


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