1999 Layout

[steve]

Is it just me or is the stone terminal © on the 1999 layout to short for a 400 metre freight train to fit in and get the loco to run round to the back. At the point where the loco would decouple (junction at the headshunt) the rear 100 metres or so would still be across the junction to the mainline, which would prevent the loco from re-attaching at the rear.

If the loco draws the majority of the train onto the headshunt then a second loco waiting on the loco spur could attach to the rear and haul it out again. But even then it looks like the last couple of wagons wouldn't reach the bunker to load/unload. And is that a reasonable statement to make about the method of operation in the exam, ie having a loco sitting around not doing a great deal?

Maybe I'm missing something, my knowledge of operational methods on these types of areas is pretty slim...I have attached a picture of the offending area.

Any suggestions gratefully received.

Steve.

[PJW]

Is it just me or is the stone terminal on the 1999 layout too short for a 400 metre freight train to fit in and get the loco to run round to the back.

If the loco draws the majority of the train onto the headshunt then a second loco waiting on the loco spur could attach to the rear and haul it out again. But even then it looks like the last couple of wagons wouldn't reach the bunker to load/unload. And is that a reasonable statement to make about the method of operation in the exam, ie having a loco sitting around not doing a great deal?
Steve.

Yes I think that it is deliberately been made far too short. Note that the Goods Loop is however long enough to contain a whole train, as are (just) the sidings alongside the station which have no defined useage. Sometimes on a layout there is just a simple siding that is not referred to by the description (in which case just provide a route in and out), but anything more substantial is likely to have a specific purpose. If there is nothing explicit, think about implicit.

Hence put together the following clues:
1. Somewhere to temporarily store an entire train, just prior to it arriving at the station prior to the stone terminal.
2. A run around loop within the stone terminal that is sufficient to run around half a train
3. Spare sidings into which two half trains can be put together again to form a full length train for its return journey.

Also as you realise it is essential to get every wagon of the train to get into position under the hopper. Unless you are going to engage in much shunting (in which case it would be a yard rather than run round loop) it requires almost the whole train being loaded to pass beyond the hopper into the long headshunt so that the last wagon can get into the desired position. Hence it is not just the distance between the clearance points of the runaround loop which acts as the limit of the train which can be handled, but also the length of the headshunt.

Your suggestion of the other loco is not likely to be looked on favourably for the reasons you state- hardly economical, still doesn't allow the handling of the entire 400m train; also whereas a single loco in a facility at any one time only need minimal signalling, where there is a locomotive there before the arrival of the train and then two independent units there is a greater need for "signalling" of some sort- though not necessarily track circuits, power points and signals.

The thing in the exam is to state your assumptions and justify your decisions. You'd get credit for recognising that the loop was too short to directly address the operational requirement and the headshunt too short to permit the entire train to be unloaded, even if you couldn't come up with a means to solve it.

I agree it can be difficult to learn about railway operations- there is no book I can recommend; I did try to put the most important elements in the Mod 2 Study Pack (has anyone registered for he Mod 2 exam this year actually received a copy yet?).

Obviously do try to take any opportunity that exists whether it be visiting a signalbox or taking an intelligent look from station platform or passing train. Being a "railway enthusiast" helps- reading books, magasine articles, visiting heritage lines. You actually missed a good public open day at Merehead quarry in Wiltshire this weekend; it was a wonderful opportunity to appreciate a significant site with very little in the way of fiixed signalling. OK it wasn't in normal operation (the public swarming everywhere, three steam tank engines running up and down their individual sidings offering brakevan and footplate trips, whilst three other mainline steam locos took it in turns to pull some of the aggregate hoppers along an arrival road as well as the local diesel fleet being "on shed" / "in works", visiting diesel locomotives parked) but it was pretty easy to envisage how it must work on a normal day.

[steve]

Thanks Peter, the solution is not at all obvious, I would never (in an exam situation) have thought to split the train and use the Goods Loop and Sidings to facilitate this. But now you have suggested it, it is the obvious and only realistic solution (though I expect there are others, no idea what though).

I think that has been an extremely valuable lesson, i.e. don't always expect the answers to jump out at you. I think that this points to experience being key and getting as much practice in as possible before the exams on as many layouts as possible.

However, in my day job if I saw a proposed layout that required this kind of freight movement through a station and across a section of mainline with 12 passenger movements an hour (plus 2 through freights) I would fall off of my chair!

Mainly because the 4 stone freight moves per day has just grown to 36!

1. arrive from A, at Goods Loop, leave 1/2 of wagons and proceed to stone yard
2. return from terminal stop on Up Main
3. shunt into Up Sidings
4. loco back onto Up Main, shunt onto Passenger Loop
5. reverse back to Goods Loop for remaining wagons
6. proceed to Stone Terminal
7. return from Stone Terminal, stop on Up Main
8. shunt into Up Sidings, pick up 1st 1/2 of wagons
9. return to A.

repeating this process 4 times a day...might infringe on capacity

As we discussed in the study group the operation in the stone terminal requires quite a bit of thought, and so will all of the necessary call-on, shunt signals, L.O.S. and stop boards etc around the Up Sidings and Goods Loop. I think I might be inclined to get as many marks as I could from other areas on the paper first, but then I suppose that there are quite a few marks to be had for getting the Stone Terminal operation "correct"...dilemma!

Steve.

[asrisaku]

Hi again

May I have comments for my attempts?

Thanks
Arnut

[PJW]

From just a glance on the screen of the layout it gives the initial impression of being quite good in as far as there aren't many errors that scream out.

One thing that I didn't like was that the down signal 111 protecting the single line over the viaduct has its overlap which locks the trailing points; this means that whilst the viaduct is in use in the opposite direction that no train can be brought up to the protecting signal and thus making the "bottleneck" effect it creates even worse.

Also it seems as if there is a missing signal from the Goods loop protecting points 404; neither are there any traps at the exit where the line joins the Passenger loop.

I'll attempt to look at over next weekend, but certainly looks as if you overall have the hang of it. Don't advise that you use highlighters in the real exam though!

Hi again

May I have comments for my attempts?

Thanks
Arnut

[asrisaku]

Dear PJW

Yesterday I reviewed my attempt and I agree with the signal 111. On the time I attempted I took so much time to consider how to protect the points and failed to understand the operation.

Points 404, Yes again. The train coming with the diverging route to the points 404 and the braking distance would be from 40Km/h(BD=125m).

I am rusty to attempt MOD2 and it took a lot of time to think and write.

Thanks for you initial comments and look forward to seeing the rest!

Arnut

[PJW]

I'll add a scan of my comments on your layout and calculations tomorrow.

The calcs were quite well presented, but do concentrate on the question asked since having demonstrated that 3 aspects provided the headway then a waste of time to do so again for 4 aspects given the question actually asked. Similarly you need to take a view re what to do for the stopping headway, since the year's paper did not specifically give a requirement. Certainly the calculation showing that a stopping train takes another 3 minutes and thus effectively occupies two consecutive train paths was worth doing, but you needed to relate this to the level of traffic to be accommodated rather than coming up with a value for "stopping headway" which does not directly relate to the question paper.

The biggest defects on the layout were
a) Not explicitly stating anything re "Method of Working" as per the bottom of the end notes
b) missing out required trap points (not only the Goods Loop as it changes to the Passenger loop, but also the Up sidings)
c) Missing signals- need to protect 404 from Goods Loop, 409 from Up Main)
d) Some signals not well positioned re their overlap locking (106 not ideal, 111 effectively unworkable),
e) Signal spacing etc. re the transition from 4 aspect to 3 aspect signalling
f) Interface to Stone Terminal

Overall though it wasn't too bad and I think should have passed if you could do it in the time allowed; there were some mistales and omissions but did give the impression that you basically know what you are doing.

regards,
PJW

Dear PJW

Yesterday I reviewed my attempt and I agree with the signal 111. On the time I attempted I took so much time to consider how to protect the points and failed to understand the operation.

Points 404, Yes again. The train coming with the diverging route to the points 404 and the braking distance would be from 40Km/h(BD=125m).

I am rusty to attempt MOD2 and it took a lot of time to think and write.

Thanks for you initial comments and look forward to seeing the rest!

Arnut

[asrisaku]

Thanks for distant splendid comments! I realize a lot of mistakes and will try best to improve and avoid them.
If I don't understand I will come back to you again.

[asrisaku]

Dear PJW

I wish to try answering method of working. It would be good to get feedbacks more.

1. The method of block working on the main lines and branch lines should be shown, together with any interface arrangements.
Main lines and branch lines use track circuit block (TCB)
Is it good enough?

2. The method of working between the stone terminal and station B should be shown.
Freight trains from station B to Stone terminal C via down branch
-loco and wagon parks at stone terminal
-loco will go to headshunt and go to Run Round and go to Cripple Siding and go back to Stone Terminal
-loco and wagon leave stone terminal by using signal 162 to down Goods Loop via down branch(Back to station B)

3. The method of working over the single line viaduct at E should be shown.
-Any freight or passenger train from Down Main park at 111(Standage 400m is proposed).
-A train from UP Main can run to station B via viaduct while the other train from Down Main stands still.
-Once the train from UP Main clear viaduct E(Last Track CN clear) the train from Down can go to section 'F'

_____________________________________________

Could you please explain a bit about slot control on 151, 309, 310 at Stone bunker? I am totally blank this topic?

Best regards, Arnut

[PJW]

1. Certainly a start and you did indeed write TCB at the uni-directional fringes with the adjacent signalboxes. I'd however have made a reference to the need for approaching train indications to the other boxes having passed the last protecting signal and vice versa, also the provision of Train Describer and Emergency Alarm as well as direct phone line from box-to-box.

Given the bi-directional single line portion over the viaduct, enhanced route locking and perhaps a direction switch should have been provided. Ditto the bi-directional Down Branch to C.

The main interface is with the Stone Terminal which could potentially have been designed to be operated from a separate local panel or directly by a shunter and it was this that would need description. However as you have drawn it, I read the design as still being controlled from the same signaller and track circuiting being provided, albeit with many of the moves being permissive and this information could have been shown on route boxes but even so some statement re the limits of TCB should have been made.


2. Given your choice of the Stone Terminal being controlled by the main signaller, then there is probably little to write re method of working between B and C. Instead though you should have said how the signaller would know that it was appropriate to clear 309 so that as the train is pulled into the headshunt that the terminal is ready to discharge the stone into the wagons as they pass underneath. Also how does the local operator get in contact with the driver if needs to stop in an emergency / adjust speed etc to avoid either the train only being half filled or alternatively all the stone spilling everywhere if things go wrong!
The signaller also needs to know that it is safe to clear 310 so that the driver can push back the now filled wagons through the stone bunker again (we don't want to trap any workers who may have needed to enter the area) and again when clearing 309 having disconnected the wagons ready for the run-round move.
Actually the control of movements in such an are are better done by a local operator who can actually concentrate on the activity, physically see what is happening and be in local radio contact with the train driver, rather than a remote signaller who has the rest of the railway under their control to worry about and could therefore be distracted.

Hence my supposition that what you have numbered 305, 307, 309, 310 and points 414 and 417 would be under the control of the Stone Bunker operator and so in a completely separate number sequence prefixed C.
Then there is a matter of "slotting" between the main signaller and this operator.

Operator at C would need to give a "slot" (i.e. an electrical control output into the main signaller's interlocking) as a pre-condition for them being able to set the oute(s) from their 151 up to the signal protecting the stone bunker - let's call it C9.

Alternatively you could have selected the boundary of the respective areas slightly different with the local operator only worrying about 307/309/310/411 and therefore the actual slots needed would be different to reflect this split. The key is that when one signal needs at least some element of control from a second operator that the ownership is allocated to one and the other is given a slot on that element which concerns them.

The operator at C would need an approaching train indication
"DB occ or DC occ w 415R" and the main signaller would need to have C's track indication CDG both to see the totality of 101's route but also to see a train on the berth of their 162.

The would need to be a direct phone between the main signaller and the operator at C and some consideration of whether any Train Description needed etc.


3. Probably not much to write. I think the key is that it should have been possible to have brought a train up to the protecting signal in EITHER direction when the viaduct in use in the opposite direction- which in your case the placement of 11 did not allow. Provision of a direction switch would have enabled the security of route locking to establish reservation in either of the Up or the Down directions in the vent that there was a need to use in degraded mode at a time when normal route setting and signal clearance not possible.

Dear PJW

I wish to try answering method of working. It would be good to get feedbacks more.

1. The method of block working on the main lines and branch lines should be shown, together with any interface arrangements.
Main lines and branch lines use track circuit block (TCB)
Is it good enough?

2. The method of working between the stone terminal and station B should be shown.
Freight trains from station B to Stone terminal C via down branch
-loco and wagon parks at stone terminal
-loco will go to headshunt and go to Run Round and go to Cripple Siding and go back to Stone Terminal
-loco and wagon leave stone terminal by using signal 162 to down Goods Loop via down branch(Back to station B)

3. The method of working over the single line viaduct at E should be shown.
-Any freight or passenger train from Down Main park at 111(Standage 400m is proposed).
-A train from UP Main can run to station B via viaduct while the other train from Down Main stands still.
-Once the train from UP Main clear viaduct E(Last Track CN clear) the train from Down can go to section 'F'

_____________________________________________

Could you please explain a bit about slot control on 151, 309, 310 at Stone bunker? I am totally blank this topic?

Best regards, Arnut