Warning signals

The train driver who, back in november 2006, crashed a freight train into a commuter train is not to blame for the accident, a judge ruled last week. This ruling was partly supported by a TU Delft researcher’s criticism of the rail signaling system.

The accident slightly injured a few dozen people and caused about a million euro in damage. The Netherlands’ national transportation investigative body (Inspectie Verkeer en Waterstaat - IVW), which compiled the official report on the accident, concluded that the train driver should be held responsible for the accident because he was not paying sufficient attention and failed to brake in time for a red stop signal. Last week however a judge ruled that the signaling system was not functioning as clearly and properly as the IVW had claimed. An article in De Telegraaf newspaper on September 5th stated that 'TU Delft researchers have been pointing out to ProRail [the national rail service company - ed.] flaws in the Dutch train signaling system for some time, but ProRail refuses to do anything about it. What’s the deal here?'

The TU Delft researcher in question turns out to be Jaap van den Top, who, for his PhD thesis, is investigating the safety of the Dutch railroad system. “Railroad signals can show one of three colors,” he explains, “which is a bit like traffic lights, but slightly different: greens means ‘go’ and red means ‘stop’, but yellow means ‘slow down and expect a red signal coming up, so be ready to brake’. So far there has been no problem with this, but there are a few places in the Netherlands, like the spot in Arnhem where this accident occurred, where the distance between two successive signals is too short for a train to brake and come to a complete stop in time. The current solution for this problem is that a short stop is preceded by two yellow signals in a row.”
But that can be confusing, Van den Top states: “Just prior to the accident in 2006, the train driver received three yellow signals in a row. After the first signal, he slowed down, expecting a red signal to come next. But instead he got another yellow signal. And then another one. The last yellow signal confused him, so he focused on that, and when the red signal came just shortly after the third yellow signal, he couldn’t stop the train in time.”

Is it true that Van den Top had already pointed out this flaw to ProRail on multiple occasions? “Well, that was a bit boldly stated by De Telegraaf,” he says. “But it’s true that I spoke to them about it. Apart from that, it’s not like I’m the one who discovered the flaw. The rail service did that itself. I read about it in a book written by the former head of rail safety. They also already came up with a solution for the problem back in 1987: make a yellow signal that is followed closely by a red signal flash. Then the driver would know for sure that he should start braking before passing the signal. But this solution has never been implemented. Perhaps they will do so now.” (NB)
 

The accident slightly injured a few dozen people and caused about a million euro in damage. The Netherlands’ national transportation investigative body (Inspectie Verkeer en Waterstaat - IVW), which compiled the official report on the accident, concluded that the train driver should be held responsible for the accident because he was not paying sufficient attention and failed to brake in time for a red stop signal. Last week however a judge ruled that the signaling system was not functioning as clearly and properly as the IVW had claimed. An article in De Telegraaf newspaper on September 5th stated that 'TU Delft researchers have been pointing out to ProRail [the national rail service company - ed.] flaws in the Dutch train signaling system for some time, but ProRail refuses to do anything about it. What’s the deal here?'

The TU Delft researcher in question turns out to be Jaap van den Top, who, for his PhD thesis, is investigating the safety of the Dutch railroad system. “Railroad signals can show one of three colors,” he explains, “which is a bit like traffic lights, but slightly different: greens means ‘go’ and red means ‘stop’, but yellow means ‘slow down and expect a red signal coming up, so be ready to brake’. So far there has been no problem with this, but there are a few places in the Netherlands, like the spot in Arnhem where this accident occurred, where the distance between two successive signals is too short for a train to brake and come to a complete stop in time. The current solution for this problem is that a short stop is preceded by two yellow signals in a row.”
But that can be confusing, Van den Top states: “Just prior to the accident in 2006, the train driver received three yellow signals in a row. After the first signal, he slowed down, expecting a red signal to come next. But instead he got another yellow signal. And then another one. The last yellow signal confused him, so he focused on that, and when the red signal came just shortly after the third yellow signal, he couldn’t stop the train in time.”

Is it true that Van den Top had already pointed out this flaw to ProRail on multiple occasions? “Well, that was a bit boldly stated by De Telegraaf,” he says. “But it’s true that I spoke to them about it. Apart from that, it’s not like I’m the one who discovered the flaw. The rail service did that itself. I read about it in a book written by the former head of rail safety. They also already came up with a solution for the problem back in 1987: make a yellow signal that is followed closely by a red signal flash. Then the driver would know for sure that he should start braking before passing the signal. But this solution has never been implemented. Perhaps they will do so now.”