Departure order signals

I managed to observe the use of the departure order signals on the S-bahn in Berlin recently at Zoo station. Instead of having a platform dispatcher with a while lollipop as in London and on many other metro systems, the dispatcher was stood on a raised platform next to a vertical control panel. When it was time for door closing, the dispatcher pressed the door closing button, lighting the door closing signal next to the starter signal. When the doors were observed by the dispatcher to be closed, then the depart button was pressed lighting the depart signal next to the starter signal. So as far as I could see, the departure order signals are to aid dispatch, rather than for train interval regulation.

Signals & train ops
Most starters at terminal stations [when departing] are cleared early, giving the train op time to prepare for a right time departure.

In areas where points are involved, the green actually indicates that all the points are securely locked and the shows the route thats been set (with 'feathers' etc if needed). If we're shown a wrong route we have to wait while the signal operator takes a release and resets the correct route. That means we'll have to re-open the doors which is considered bad practice.


I'm not saying that some form of indication prior to a green is a bad idea, I just wonder if it would make much difference. Perhaps you can report back on any conclusions from your visit stephenk?

Customer indications
I believe the Central line dot matrix boards show ***Mind The Doors*** when the train op recieves his target speed / gets a clear signal.

On LUL, at terminus stations, in most cases, once the platform starter clears the indicator board will change to show the platform of the next train - thus putting off potential passengers from boarding a train that is about to depart.

Whilst LUL do make use of white batons at some busy stations [which a 'trained punter' will recognise], having an indication that a train is about to depart is not considered a good idea because it could encourage punters to run along platforms - if they trip up they could have a nasty accident. Also we'd get more of 'em getting stuck in doors

As far as I could see, this departure order signal system in Berlin was just a replacement for the white baton, and thus did not occur unless there was already a green signal.

At Prague, a headway clock was used to tell drivers when to close doors and depart - e.g for a 1:55 headway at a terminus, the driver would start the door closing procedure at approx 1:40. However as everything ran like clockwork and the crossover always cleared at approx 1:25, I never had the chance to see if the door closing procedure would have been started with a red starter.



I think the Central Line has a countdown system, that counts down from 15secs to expected departure time. The ***Mind The Doors*** message appears at 10secs before expected departure time. I'm sure a few Central Line experts may correct me if I'm wrong here.

The present system of the "next platform" indicator changing when the train gets a green light at a terminus is all well and good for present headways. But under new signalling the plans are to run up to 33tph from termini such as Brixton. Given that it may take 85-90secs to get a train out and in through the crossover (I would be interested to know the exact planned figures), that leaves just 20-25secs operating margin, which is not taking into account the door closing time. When you take into account the door closing time (green signal to train starting) of 10-20secs, that leaves just 5-15secs of operating margin for the next train delayed!

So personally I think a headway clock, or a countdown system such as that already used on the Central Line would be of use, but with added predictive ability for the conflicting move (maybe initiated by the incoming train being detected as entering the platform approx 15-20secs ahead of the crossover clearing). A predictive system could then change the "next train" indicaters at a pre-defined time before the expected door closing time - e.g next train changes 17secs to departure, driver initiates door closing at 10secs prior to departure.

I do see the point that it may just make customers run for a train instead of wait for the next one. Maybe something needs to be done to try and deter this. Some metros use platform staff located around the doors nearest to the platform entrance to deter late arrivals. Other's use different language such as "please wait", instead of "mind the doors". Maybe a flashing message at the platform entrance reading "Do not board"? Certainly changing human behaviour for efficient dispatch is harder than changing technology for an efficient dispatch!