Leaves On The Line – A Cautionary Tale

The press loves to trivialise potentially serious events when their staff find rail journeys taking a few minutes longer than usual, and one target is “leaves on the line” (examples from the Mail HERE, HERE and HERE). That this is a potentially lethal problem – Network Rail expends significant resources tackling it every Autumn – can be seen when it hits countries that don’t normally experience it.

An Intercity train from Porto to Lisbon pauses by the signal tower at Entroncamento. The train in the collision looked more or less like this

Leaf fall is almost unheard of on the Iberian peninsula. But last January, there had been heavy rain across Portugal, with strong winds and humid conditions to follow. Refer, the company that looks after rail infrastructure, had sent teams out to deal with leaf fall incidents. But there had been no accidents until the evening of January 21, on the main Lisbon to Porto line.

The Regional train was made up of two of these multiple units

Here, there is continuous signalling and train protection, but that cannot combat the compacted leaf mulch that builds up on the rail head. At around 2110 hours, a Regional (stopping) train from Entroncamento to Coimbra was approaching the station at Alfarelos. It should have stopped at the red signal in rear of the station before being put in the loop for a following Intercity train to pass.

Diagram showing the sequence of events (from Público.pt)

When the driver applied the brake, though, instead of the train slowing, it actually accelerated. There is a downwards gradient, and the train was sliding on a film of compacted leaves. After overrunning the red signal, the train protection system applied the emergency brake. By this time, the train had overshot the points that would have switched it away from the main line.

Aftermath of the collision. The locomotive of the Intercity train is covered in wreckage from the empty multiple unit. The blue plastic fragments are seats

But before any action could be taken by the signaller, the Intercity from Lisbon to Porto and Braga encountered the same problem. As can be seen from the diagram, the train began to slow as expected, but then lost grip and also overran the red signal in rear of Alfarelos station. Automatic application of the emergency brake could not prevent it rear-ending the Regional train at 42km/h.

Signals, train protection systems and all on-board equipment were in good working order. It couldn’t prevent the collision. And the effect of that collision was severe: the locomotive of the Intercity train embedded itself in the Regional, totalling the two rear coaches. Fortunately, that evening the Regional train was formed of two units with the rear one locked out. The damaged coaches were empty.

Otherwise the accident could have been deadly. In the UK, drivers know what to expect in leaf fall season. In countries where it needs a freak combination of weather events – and happens at an equally unexpected time of year – there is nothing trivial or jokey about “leaves on the line”. There were a lot of passengers on board the Intercity train that evening. It could have been a lot worse.

That’s something to bear in mind when the press starts up about it next Autumn.