(24-06-2009, 12:58 PM)peternrz Wrote: I am submitting a corrected answer.
Please explain meaning of " run round" as per Note 6 on the layout.
Locomotive pulls vehicles along the branch from the colliery in the down direction and hence on the righthand end as seen in diagram. It stops at 71 signal, uncouples and leaves them in the Up Loop. The run round move is for the locomotive now to get to the other ens of its train, in this case it has to cross to Down Main via 101R, get behind 200, then via 202, 68 to get behind 67 and then needs the PL aspect to make a permissive move back onto its train. Loco is now at left hand end and could pull the wagons in the up direction. In this example there is no suitable connection so it actually needs to set-back its entire train propelling wagons onto the Up Main. Not highly desireable and such moves towards LOS should be of the shortest practicable distance.
You do need to understand train operations in order to signal the layout in mod 2 or do Control Tables in mod3!
(24-06-2009, 12:58 PM)peternrz Wrote: Also,if MA200B(S) requires MA202 off as per Note 6 on the same layout; does MA202 remain the exit signal for this route?
Indeed MA202 is the exit of MA200B(S). However the ASPECT will remain at red until such time as MA202 shows proceed. A driver will probably not expect to stop at MA202 as in their mind they are undertaking a "run round"; being just a GPL there is a potential SPAD risk. This is avoided by holding the loco at MA200 until the driver's potential expectation can be made reality. On certain layouts it might be operational essential to free up the layout (and tus such a control would be omitted but perhaps with some other partial mitigation) but on this one there is not a great deal of benefit in allowing the loco to drop down to MA202 as not in the way of anything else whilst waiting at MA200- hence better to be that little bit safer by imposing the control specified.
On a mod 3 layout you may care to put such a control in because you feel that your railway's practice would do so; however if the control is actually stated in text or a route box then you MUST put it in (or at least explain that it is NOT a practice appropriate to the railway on whose standards you are basing your answer)
PJW