Post by Deleted on Dec 7, 2011 23:56:07 GMT
I agree with tridentalx.
If anything, not commissioning the bi-di capability on the JL has saved money - even on just the TBTC. And that's without considering all the extra costs assocaited with the other infrastrucure changes mentioned above which would be needed.
Thales obviously require all moves to be tested with real trains. If bi-di was everywhere the amount of testing (and therfore closures) that would have had to be done would have been much greater. Then there are all the extra Direction Indicators, Rail Gap Indicators and Route Secure Indicators that would be needed for trains running the 'wrong' way.
There are also other advantages to not having bi-di. For example it has allowed the axle counters to be optimisted to give the best performance in one direction. If they had to allow for signalled moves in the opposite direction then the main performance would suffer.
Also we should remember that in DLR and other places the 'driver' doesn't have to be at the front of the train. Just getting a JL driver to the back of a packed train stopped in a tunnel so it could run back to the previous station if there was a problem could be impossible.
If anything, not commissioning the bi-di capability on the JL has saved money - even on just the TBTC. And that's without considering all the extra costs assocaited with the other infrastrucure changes mentioned above which would be needed.
Thales obviously require all moves to be tested with real trains. If bi-di was everywhere the amount of testing (and therfore closures) that would have had to be done would have been much greater. Then there are all the extra Direction Indicators, Rail Gap Indicators and Route Secure Indicators that would be needed for trains running the 'wrong' way.
There are also other advantages to not having bi-di. For example it has allowed the axle counters to be optimisted to give the best performance in one direction. If they had to allow for signalled moves in the opposite direction then the main performance would suffer.
Also we should remember that in DLR and other places the 'driver' doesn't have to be at the front of the train. Just getting a JL driver to the back of a packed train stopped in a tunnel so it could run back to the previous station if there was a problem could be impossible.
