Topic: | Re:Re:Piccadilly trains held at Acton Town | |
Posted by: | Thomas Barry | |
Date/Time: | 29/04/15 12:39:00 |
"I don't know the exact details of the Piccadilly line signalling but I think it is something called "fixed block" so the track is divided into blocks and a train simply isn't permitted into a block until the train in front leaves it. " It's simpler than that - the signalling at Acton Town is designed to let trains approach the station slowly and they can safely run quite closely together, because all trains stop. The signalling at TG, on the Piccadilly, is designed to let trains approach at speed, because the peak service does not stop - this means there are fewer trains per mile but you maintain the throughput because they're travelling faster. Changing the TG signalling to allow Acton Town style closeness on the approach was always dismissed because TfL said that new superduper signalling was going in next year (or whenever) and we should wait for that. With the new system you don't have fixed signals and the advantage is that since the train and computer are in continuous contact the computer can instantly tell a train to speed up because the train in front has moved on, plus computer control is more precise than a human driver so you can reliably design your timetable for more frequent trains running more closely together. Interesting comments on the previous upgrades here: http://www.railway-technical.com/Northern-Interview-article-for-MR-v5.pdf |