09-09-2010, 09:13 PM
(09-09-2010, 07:26 PM)Peter Wrote: TPWS does not prevent SPADs, it mitigates the effect of them by making sure that the train comes to a stand within the "Safe Overrun Distance".
Perhaps better worded that TPWS is not INTENDED to prevent SPADs and the TSS certainly does not.
Depending on the train and the set speed and position of the OSS then because it does trigger an emergency brake application some distance prior to the signal, then it is ceertainly possible that the train may come to rest before it even gets to the signal- it is rare but there have been documented cases of this.
When they were first installed the bufferstop OSS freuently stopped a train from even reaching as far down the platform as it should- let alone the buffers.
I agree though that in the overall scheme of things, what Peter said was 99% true.
PJW