02-10-2008, 06:09 PM
nthomso3 Wrote:Surely you could put just a IPL at 1300m and use it as a preset shunt for main routes along the DOWN VALLEY BRANCH?
There should be no shunt moves up to such a signal over the viaduct and therefore nothing will stop at it!
Indeed. probert1 has correctly explained the options for getting stock from the DM platform into the siding. I think that I's put a GPL at 1300 as suggested by nthomso3 which would be a pre-set shunt as described. Indeed probably also another one at 1750 protecting the crossovertowards the branch and sidings- this is also useful for train from UM platform to reverse. Obviously if you did decide to place a main running signal just a little way onto the viaduct then it would be given a PL aspect to read up to the GPL at 1750; this rather pre-supposes that the driver can walk through the rolling stock from one cab to the other without descending to ballast level.
nthomso3 is quite right- there would be ne shunt move up to the GPL at 1300; it would either be used for a train to change direction or would be pre-set by the main signal in rear and thus no moving train would ever encounter it at red.
PJW