length needed for runaround at a Terminus

[cabbie37]

I'm at the mulling stage on a layout that will be based on boards 1200mm long. As the setting will be a small terminus, I'm trying to work out platform lengths, etc that I will need for my envisaged trains. The likely sets will be 3 x 59ft Maunsell plus a 4 wheel van of 36ft. Lets say likely motive power to be a T9, length 64ft. Gives a total overall length (roughly) of a train length of 280ft = 1120mm. I admit, these are rough numbers at this stage. To add a runaround, I need enough room to detach the loco, run forward over the point and then have enough space so that the loco doesn't foul the leading carriage as it traverses into the release road. This is where I am struggling to work out the length needed to permit that. Can anyone help me work through my problem? I want to decide how the board joins and platform length and any other trackwork might work (eg a bay platform, perhaps some other parallel track that could act as siding or a small good shed etc) before I start thinking this through in detail.. 

 

The other option would be not to have a runaround and have the incoming loco released by a station pilot removing the carriage stock first. Though I think that would be unlikely to be prototypical operation for the sort of terminus I envisage.

 

Many thanks in advance for pointers...

[PMP]

What scale and track are you using? The ‘geometry’ of the points will determine the length required, allowing for clearances for the stock.

[cabbie37]

Sorry, yes, I should have said that. 00 and Peco code 75...

 

[Nearholmer]

If you arrange things so that the train is clear of the crossover as below, you won't go wrong in model railway terms. You can sometimes squeeze a bit more, depending upon track-spacing, turnout angle/radius, loco size etc, but its best not to plan for that.

 

 

Edited October 5, 2020 by Nearholmer

[cabbie37]

Thanks @Nearholmer, that is a perfect explanation. As a space saver, would small radius points work here or should I be thinking about either medium or large radius points to give a more realistic look? I'm afraid I'm not very good at this track stuff!! (but learning - everyday is a school day!)

 

Hugh

[Nearholmer]

Larger radius points will always look more realistic, but space constraints sometimes dictate small radius. Given that it is naturally a place for slow-speed moves, if you have to use small radius points anywhere to save space, the loco release is probably the place to do it, rather than in the station throat, where long coaches will highlight the tight curves.

[Zomboid]

The general rule is that longer points look better (depending on your priorities, there's more to a layout then just looking good), but loco release points would be the first to go to smaller radius if you're trying to cut down on length. You don't have to worry about how a train will look running through them, you see...

 

So essentially, you'd probably be fine having those as short ones.

[cabbie37]

Thanks again both. Looking at the PECO web site templates, the difference between small, medium and large point lengths are

 

Small: 210mm

 

Medium: 225mm

 

Large: 250mm(?)

 

Large may prove a little generous, but the diffference between small and medium is less marked. As a rule, I am a believer in 'less is more' so won't be trying to cover every square inch of the boards with track.

[cabbie37]

May I develop this question slightly. Now I have a clear idea of how to allow for the required clearances, I have started to think about the use of the 'release' road. I had it in my mind that this would be a two platform station with platforms on either side of the two tracks we have been talking about. Obviously there would not be so much traffic coming and going that there might be two trains in the station at any one time - or would there? I'm now thinking would the second platform, on the release road, be a bit of a white elephant? I'm sure not, but can't imagine how that would work - unless the points arrangement became a double crossover, or the train that used that platform was pull-push (which is planned for..). I guess what I don't understand is how a tereminus like this would have been used. I'm afraid my experiences at Bedhampton Halt and catching the Hayling Billy for a day at the seaside as a lad don't help in this instance...

[Nearholmer]

In theory, you can work a double track between two platforms with a single release crossover in the same way as Hayling: arrive; run-round; shunt train to other platform; next train arrives; first train departs.

 

But, it is more practical to have the Hayling arrangement, with a bay for departures at busy times, because it accommodates delays better - the newly arrived train can run-round before the other train leaves if necessary. In  the real world, it also fits better on many sites, because the main building is on one side, not stuck on the end, and it is simpler to staff and to handle barrow-loads of parcels etc.

 

Both termini on my layout use the Hayling-style plan, and are simple to work with a quite intensive service.

 

 

 

Edited October 5, 2020 by Nearholmer

[ejstubbs]

3 minutes ago, Nearholmer said:

On busy days, a train would arrive in the main platform, run-round, then shunt to the bay, departing as soon as the next train arrived at the main platform.

 

I must be missing something here, but I can't see there's anything to stop exactly the same overall arrival and departure sequence with two platform roads joined by a release crossover.  First train arrives, loco runs round and the train's ready to depart (without needing to shunt).    Second train arrives, first train can depart immediately the second train is in its platform.  The only difference I can see with the first incoming train being shunted in to the bay is that the loco of the second incoming train can run round its train without being obliged to wait for the first incoming train to depart in order to free up the run-round loop.  Please explain if I am misunderstanding (I can always blame it on the beer ).

 

Arguably there is also an additional cost in providing the bay road, given that the run-round loop has to be there in both cases...

[Nearholmer]

I kept editing my post until it became garbled, so wiped it and started again ......

 

I can’t blame beer, cos I haven’t had any, so will blame the weather instead.

[Dagworth]

14 minutes ago, Nearholmer said:

I can’t blame beer, cos I haven’t had any

I think I can see the problem here....

 

Andi

[Dungrange]

I think the other difference is that without the bay platform, the second train would have to be a locomotive length shorter, so that the front of the locomotive stops before the clearance point of the crossover, whereas with the first train the locomotive only needs to stop such that the front coach is clear of the clearance point.  If the second train is the same length and the platforms are also the same length, then in would be necessary to detrain the passengers and then set back a locomotive length to permit the run round.

[DCB]

The advantage of the island platform or bay over platforms to the sides of the track in model form is discovered  when you have a derailment between platforms. One train fouls the other.Ouch.   It was not that common to have two passenger trains in a small terminus station at the same time.  Quite often what appears to be a passenger Bay is actually a dock with raised platforms which make wagons easier to load but are too high (3ft plus) to allow carriage doors to open.

[cabbie37]

Thank you all for your thoughts. I think what I need to do is, rather than starting with a track plan, I should consider what train movements I want to support and *then* put together a track plan that allows that. I have already planned the train formation I outlined in an earlier post, then there will be a push-pull service coming and going, at least one train that has a BCK detached from a London service, probably held in a siding through the day for the return journey on a later train, one that has a milk tanker attached (both full at the end of the day and the empty return the next morning and then another service with an ex-LSWR '4 1/2' set plus the occasional 2 carriage local trains behind (say) an M7 - along with the occasional freight movement, of course. I will have an 0-6-0 tank loco on duty that will act as a shunting loco which could also act as a station pilot when needed (although, in this particular setting, that might be Rule 1 inspired). If I sketch out a series of train movements, that would be a start. At that point, of course, I do need them to have a semblance of prototypical movements...

[Joseph_Pestell]

Sounds like a good plan. After all, it is what happens on the real railway.

 

What you have described by way of a service sounds a lot like Sidmouth which in reality was quite large but can be compressed without losing any of the operating interest.

[cabbie37]

It's interesting you should say that, I was only looking at the Sidmouth track plan for inspiration the other day. Needs closer study perhaps...

 

Edit: Yes, Sidmouth seems a perfect example of what I am attempting to create. The down side is, of course, that many others have already done so (I've just been looking at Richard Harpur's excellent P4 layout, for example) and I'd like to do something that had my own 'stamp' on it. I am going to be working with 4 1200x600 boards, so I have length, perhaps, but lack a bit of depth. We shall see...

Edited October 6, 2020 by cabbie37
more research!

[Siberian Snooper]

If you want a fairly intensive passenger service,  you could have an island platform and run round loops on both sides. The other alternative is like Uxbridge Vine Street. The train arrives in the arrival platform, detrains, set back on to the departure line and run round, set back into the departure platform. Once the loco on the first train is back on the departure line a second train can arrive at any time.

 

 

[woodenhead]

5 hours ago, cabbie37 said:

Thank you all for your thoughts. I think what I need to do is, rather than starting with a track plan, I should consider what train movements I want to support and *then* put together a track plan that allows that. I have already planned the train formation I outlined in an earlier post, then there will be a push-pull service coming and going, at least one train that has a BCK detached from a London service, probably held in a siding through the day for the return journey on a later train, one that has a milk tanker attached (both full at the end of the day and the empty return the next morning and then another service with an ex-LSWR '4 1/2' set plus the occasional 2 carriage local trains behind (say) an M7 - along with the occasional freight movement, of course. I will have an 0-6-0 tank loco on duty that will act as a shunting loco which could also act as a station pilot when needed (although, in this particular setting, that might be Rule 1 inspired). If I sketch out a series of train movements, that would be a start. At that point, of course, I do need them to have a semblance of prototypical movements...

Sounds rather similar to a past layout of my own - except I allowed the ACE (or a portion of it!!) to also arrive.

 

[RobinofLoxley]

If you have access to a PC you could consider downloading the demo version of Anyrail. A big help with dimensions generally. You can make plans for individual board sections to stay within the  50 track piece limit.

 

Never worry about imitation.

[DCB]

Bude might be worth a look as a track plan.  It had a long bay platform and a harbour branch which could be interesting traffic wise.

The Southern didn't really go in for 0-6-0 tanks, apart from the Terriers based on the Brighton and South Eastern sections they were mainly used as shunters at larger marshalling yards. One was at Meldon Quarry, I think Plymouth had one.  The Southern equivalent to the GWR 0-6-0 Pannier Tank was the 0-4-4T the 02 and to a lesser extent the M7.   Shunting, local goods. local passenger.   The Southern used N class as heavy goods locos west of Exeter so a  T9. and N and an 02 should cover most trains.   BR Std 3MT 2-6-2Ts also worked the line,ad maybe Bob and WC pacifics and BR std 2 2-6-2T and std 4  2-6-4T.    GWR is my thing really so a bit wooly re Southern's strange habits.

[Keith Addenbrooke]

If I might add to these observations - which are (in my view as well) quite correct:

 

On 05/10/2020 at 22:09, Nearholmer said:

Larger radius points will always look more realistic, but space constraints sometimes dictate small radius. Given that it is naturally a place for slow-speed moves, if you have to use small radius points anywhere to save space, the loco release is probably the place to do it, rather than in the station throat, where long coaches will highlight the tight curves.

 

On 05/10/2020 at 22:11, Zomboid said:

The general rule is that longer points look better (depending on your priorities, there's more to a layout then just looking good), but loco release points would be the first to go to smaller radius if you're trying to cut down on length. You don't have to worry about how a train will look running through them, you see...

 

So essentially, you'd probably be fine having those as short ones.

 

I would add that, depending on how your station is arranged, the loco release / crossover may also be partly obscured by the Station building, or perhaps a platform awning or overhead roof as well, adding to the justification.

 

As a variation (when the station has one platform - so may not apply here), there can be merit in this:

 

 

The reason is that there is no “S-curve.”  If you are running tender engines, such as a T9 (lovely engine) this can help.

 

Edited October 5, 2022 by Keith Addenbrooke
Replacement photo as original no longer available

[Keith Addenbrooke]

If I may offer a second thought, 

 

On 05/10/2020 at 22:45, cabbie37 said:

May I develop this question slightly. Now I have a clear idea of how to allow for the required clearances, I have started to think about the use of the 'release' road. I had it in my mind that this would be a two platform station with platforms on either side of the two tracks we have been talking about. Obviously there would not be so much traffic coming and going that there might be two trains in the station at any one time - or would there? I'm now thinking would the second platform, on the release road, be a bit of a white elephant? I'm sure not, but can't imagine how that would work - unless the points arrangement became a double crossover, or the train that used that platform was pull-push (which is planned for..). I guess what I don't understand is how a tereminus like this would have been used. I'm afraid my experiences at Bedhampton Halt and catching the Hayling Billy for a day at the seaside as a lad don't help in this instance...

If I may offer a second thought, which I’m afraid is a GWR example not Southern (sorry), the station at Ashburton was arranged with the “apparent” ‘second’ platform was never (as far as I know) used for passengers, but was used as an extension of the cattle dock on market days, even though it was under the overall roof.  This kind of arrangement, while it does involve the S-curve on the crossover, is an efficient way of providing an extra siding for minimal (or zero) extra model railway space.

 

 

Just a thought, Keith.

Edited October 5, 2022 by Keith Addenbrooke
Edited for text only as photo no longer available

[Zomboid]

5 hours ago, cabbie37 said:

I am going to be working with 4 1200x600 boards

That's plenty of space. Do they have to be set up in a straight line? I've spent the last few days looking at a design for a similar amount of boards arranged differently (the small shelf & circuit thread), which might not be anything like what you're after... Just if you have that choice then you might want to consider options other than a 4800 X 600 straight line.