(30-09-2015, 09:49 AM)prabhakarmishra Wrote: Hi,
Thank you all for your comments. It is very useful.
There was some doubt regarding clearance points and providing signal between two running lines. Now it is clear.
I agree that driver will not be able to see 306 PL (about 400m away!) and the option of having less controlled signalling here.
But ( just curiosity) can you suggest a way to (controlled) signal train movement after run round into siding?
Is option of providing another GPL near 1111B is suitable?
What are those risks that you want us to focus ?
"Propelling a long freight train always has its risks; when the signals are GPLs and there is a set of gates that need to be opened from being across the line and handpoints involved,if not careful it is an accident waiting to happen!"
I'm new in this field. Apologies if I asked some thing obvious .
Thanks
Prabhakar
Unless the running lines are widely spaced (for example there is generally a "10 foot" between each pair of tracks on a 4 track railway, then there isn't the clearance for a straight post signal. In the UK the only signals placed between normally spaced running lines have to fit within the "915mm high above rail height" space within the structure gauge; in practice this means a GPL signal with a route indicator or a ground mounted main 3 aspect signal head (rare but occasionally used from exit of sidings or terminal platforms or as a co-actor associated with a normal main signal).
Yes you could provide more signals to allow a signalled run-round move.
- If (over)signalling this area, I'd have placed 308 (but only a Red/Yellow) at about the "0900" datum (even if giving an overlap on a Goods line it wouldn't be restrictive since there can be no other train in the area!); braking isn't an issue since only 40km/h
- 306 would be almost as you had drawn it- you could get a ground mounted red main aspect with PL above it between the line and the loop. At 40km/h it would be ok when loco pulling its train; the problem is the PL visibility after the loco has run around and is pushing the 400m train. You'd probably have to put a couple of banners for the Up direction placed to the right (i.e. above the line on the plan) of the Goods line; indeed it may be best to have placed 306 as a normal straight post on this "wrong" side of the line as well. However this would then require the driver to do the setback move from the furthest end driving cab not only propelling their train but with neck contorted looking back over their shoulder out of the window as well; not only would they be able to see very little of use but it would be most uncomfortable and a distraction- this would be for the length of the movement which must be some 1200m and that is going to take perhaps 3-4 minutes, so NOT A GOOD IDEA! The alternative of cantilevering 306 and its banners over from the cess of the runround loop would add tremendously to costs- all ready very high for what is a one freight per hour service.
[As I said before I'd not signal it; I'd use the guard with a radio link to the driver, but you did ask........]
- 201 would be as you had drawn it but without the Auto facility!.
- You'd need a GPL at the tips of 1112A to be able to get into siding (the loco would have obviously to be to the right of the wagon(s) so perhaps it is one that has been extracted from a train being shunted within the yard sidings). Also need a GPL (broadly opposite 201) to get out of that siding again.
- There is probably little value in a signal at datum "0780" as 201B(S) may as well read to the buffers in the neck, but you would need GPL 505 to route back onto the Goods line
- If you provided GPL 506 to give a signalled move into the yard, then you should at very least detect the gates open but probably also lock them open whilst that route was set, so that would need to be depicted, perhaps as a gatelock instrument.
- Alternatively you would probably be better to define the 306 PL to read only as far as a red roundel mounted on the gates themselves (no overlap!) and make it handsignalling from that boundary- but actually I would have provided a "STOP and Wait Instructions" reflectorised board just prior to those gates in lieu of GPL 506.
- Similarly in the opposite direction would provide such STOP boards at the exit of each siding (in lieu of the unidentified GPLS on your plan) and authorise verbally the driver to pass over handpoints, through the gates up to the main signalbox's first signal 201. However there would need to be some means of ensuring that the yard shunter was not authorising a train to leave at the same time that the signaller was routing one in the oposite direction. so some form of shunter's acceptance input into the main signalling system to make sure that there was not "a proper misunderstanding" could occur.
However I think that the run round would best be controlled locally
- control the points from mechanical levers of Ground Frames [#] positioned at each end of the loop, released by a Train Staff (or similar) which is what authorised the freight train to enter the last portion of the line beyond station B.
- these mechanical levers would be operated by the train's guard who could then go on foot to open the gates, operate handpoint within the yard sidings and check the siding ready to receive the train. From there they could use the radio to continually assure the driver that they should be continuing to propel their train and then walk alongside the rear of the train as it gets pushed into a siding in order to give appropriate warning to the driver prior to the position to stop.
- would then walk up the side of the train, uncouple the loco, verbally authorise towards the gate, change the handpoint, authorise the driver towards them and come next to the other rake of vehicles and then couple to them.
No question is too obvious to be worth asking
PJW