(03-03-2009, 09:43 AM)alexgoei Wrote: 1 How then would the reduction in overlap to 80 metres be determined? Is there any other standard other than GK/RT0064 that can be referred to? Or do we have to calculate it along the lines you mentioned in your earlier reply?
There is an unofficial spreadsheet but never published. In some quarters there is a reluctance to face up to controlling risk on the balance of probability. Everyone has always known that TPWS is not 100% train protection, it does far more than we could have reasonably hope for yet there are always those who wish to "guild the lily". A whole lot of politics between the Infrastructure Manager and the Train Operating Companies relating to "whose risk it is".........
Not really relevant from perspective of Mod 2 IRSE exam but a potential question in mod1, mod 3 or mod 7 perhaps.
Best I can do is refer you to a paper on TPWS I wrote some years ago which I have added as an attachment (was previously on main IRSE site following that YM conference but now removed I think to make way for more recent material).
Part 2 of your question I'll address later.
PJW