Yard access from a main line

[BluenGreyAnorak]

I wonder if anybody can give me any advice on how this should work? On the layout that I'm planning will be a yard accessed from a twin track main line that i'd initially designed as a simple combination of a trailing point and a single slip like this:

 

As you can see though, due to space limitations this junction will be located between the bottom of a gradient and a tunnel mouth and I'm now wondering if this arrangement is actually appropriate. Trains for the yard will approach, from a fiddle yard, on the down line but can leave in either direction. This would mean though that a train would have to stop inside the tunnel before setting back into the yard. What I'm wondering is, given the surrounding features, should the junction be arranged so that trains can enter the yard straight from the main line without having to reverse? Is that arrangement likely to be more prototypical or is either acceptable? Or is there some completely different arrangement that would be more suitable?

 

Thanks in advance for any advice

[The Stationmaster]

It might be on but I'll wait until I can see the plan before being more committal with an answer.

[BluenGreyAnorak]

Thanks Mike, much appreciated. I'd forgotten about that as pictures seem to be working in the browser that I'm using.

[The Stationmaster]

Thanks Mike, much appreciated. I'd forgotten about that as pictures seem to be working in the browser that I'm using.

 

Could well be **!%&* AOL strikes again then

[BR60103]

It could be that, as one direction requires a reverse move in the tunnel, the yard is only worked in the other direction. You might one of those stations that are situated between 2 tunnel mouths to see what happened.

[Kenton]

My initial thoughts were along the lines of how is this going to be signalled? Is the driver going to have sufficient vision of the signal and crossing from how far in the tunnel before setting back across the up line? Also just what is off to the left along the main? If there is space (in the prototype) off to the left then a loop may have been used eliminating any reversing maneuver.

 

The nature of the siding, the type of traffic both on the main and to the siding may also play a part.

[BluenGreyAnorak]

Ah ha, I guessed somebody might ask that The truth is I'm not really sure yet until I've built the base board and have a better feel for the amount of space available. The ideas that I'm mulling over include a paper mill, because of the variety of traffic that it would allow for, or exchange sidings and a military depot that would let me to indulge another interest. I was really trying to establish if I was miles off with the general principle.

 

I'm not sure how it would be signalled either - that was partly what made me ask the question. I didn't know if there were any special arrangments to deal with manoeuvres in and around tunnels.

 

As for what's along the main to the left, I'm not sure I understand what you mean by 'in the prototype'? This isn't based on a real specific location, although the layout will generally have a Western Region feel to it. On the layout, the line continues up and around to the left until it clears another line that passes underneath.

 

 

 

It could be that, as one direction requires a reverse move in the tunnel, the yard is only worked in the other direction. You might one of those stations that are situated between 2 tunnel mouths to see what happened.

 

Yeah, I see what you mean. It'd completely ###### up the rest of the layout plan though

 

I suppose that where this is leading me is, if the proximity of the tunnel makes the plan as shown a non-starter, would a facing crossover be an acceptable alternative? That way, trains approaching on the down would drive straight off the main and trains leaving on the up would leave without having to reverse out.

[Kenton]

The problem with that might be how much space you have - along with how the industry at the end of the siding is arranged.

 

Tunnels tend to only spring out of the ground in urban areas where the city sits immediately above on the tunnel, in the non-urban environment they are used to avoid natural landscape features which generally do not spring suddenly out of the ground. OK I can think of some exceptions along cliff faces...

You also would have the problem - in fact you have it already that the tunnel is at the bottom of an incline - once again unnatural geography. Any siding coming off at the top of the incline is also going to be difficult to manage if it too is on any sort of incline as model wagons do not usually have working brakes.

[BluenGreyAnorak]

Yeah, I appreciate the issues of geography. As it happens, the tunnel is let into a cliff face and a gradient effectively leading down to it is a compromise that I'm willing to accept in order to achieve what I'm trying to represent overall.

 

The amount of space that I have for whatever the junction serves isn't too much of a problem as I'll cut my cloth accordingly. I'm really just trying to establish the prinicples that would govern the operation of such a junction in close proximity to a tunnel mouth.

 

 

[The Stationmaster]

Still no pics for me so I can't say overmuch but a facing crossover would be a 'no-no' in most pre 1970s track layouts (so therefore what it serves would also have to be post 1970s) and shunting back out of a tunnel isn't all that difficult once you know how it's done (but preferably not with a long train).

[scotcent]

I wonder if anybody can give me any advice on how this should work? On the layout that I'm planning will be a yard accessed from a twin track main line that i'd initially designed as a simple combination of a trailing point and a single slip like this:

 

As you can see though, due to space limitations this junction will be located between the bottom of a gradient and a tunnel mouth and I'm now wondering if this arrangement is actually appropriate. Trains for the yard will approach, from a fiddle yard, on the down line but can leave in either direction. This would mean though that a train would have to stop inside the tunnel before setting back into the yard. What I'm wondering is, given the surrounding features, should the junction be arranged so that trains can enter the yard straight from the main line without having to reverse? Is that arrangement likely to be more prototypical or is either acceptable? Or is there some completely different arrangement that would be more suitable?

 

Thanks in advance for any advice

 

I would have thought that in steam days the facing connection from the up line would have been unlikely. The single slip would have been the other way, i.e a trailing crossover between the main lines, with a trailing connection from the down line to the yard. Alternatively, or perhaps as well, there could be a trailing connection from the up line into a headshunt, or even into the other end of the yard. Either way there would have been a trap point in the yard exit to protect the main line. Facing points were not generally popular on main lines -- more so with some companies than others. Mind you I can produce an example of a pre grouping facing single slip in the fast road, so there's a prototype for everything! In more modern times facing points have become much more common, and layouts much simplified. Your location would probably have the crossover with a connection into the yard immediately following. However this would take more space, and the layout as you have drawn it would be quite feasible. As to the gradient, in days of loose coupled wagons there were lots of rules to ensure wagons weren't left to roll away downhill while shunting was going on. However at the bottom of a hill this wouldn't be an issue.

 

Allan

[BluenGreyAnorak]

Thanks for that, Allan. This layout will be set in the late '70's.

 

I'd be relaxed about loosing the slip and having a crossover with the yard connection immediately following, if that's a more prototypical arrangement for the period. I just want to understand how it should work near to the tunnel mouth.

 

I'll be interested to hear Mikes' take on it when he can see the pics, as it sounds like he may have the solution I need I'd hazard a guess at trains no greater than about tens wagons.

[beast66606]

At the moment I can only see pics by doing a copy and paste but I'm sure Andy and the team are working on it so happy to leave them to it.

 

As has been said the facing single slip is highly unlikely, although not totally unknown. I would make it a trailing slip. Don't forget to provide some form of trap to protect the yard exit.

 

Kenton - signalling that wouldn't be an issue, underslung / ground mounted / wrong side of line are all things I've seen to get around sighting issues.

 

hth,

[Chrislock]

I can't imagine it being prototypical for a double track mainline to have anything else but a layby loop from which the siding(s) would fan.

Railways were very nervous about goods trains messing about on mainlines.

What railway company are you modelling?

[BluenGreyAnorak]

As has been said the facing single slip is highly unlikely, although not totally unknown. I would make it a trailing slip.

Ok, bare with me here whilst I make sure I understand this bit: a trailing point on the down and trailing slip on the up would give me access to and from the down to the yard, but no access out onto the up, yes? If so, that's not going to work - I need trains to arrive at the yard on the down from the fiddleyard and return on the up. If everything else works out space-wise, I may also have the option of returning to the fiddleyard by continuing on the down, but that's really an added extra for increased operational interest.

 

I've been mulling this over a bit more and have come up with the following alternative, which I think removes the concerns about facing slips and the like whilst still giving me operational flexibility. Is this likely to be a more acceptable arrangement?

 

 

Don't forget to provide some form of trap to protect the yard exit.

Noted and understood I've read several posts by yourself and others on the old forum about such things so have a good idea about what's needed. I'll deal with that once I've got the yard access cracked though.

 

I can't imagine it being prototypical for a double track mainline to have anything else but a layby loop from which the siding(s) would fan.

Railways were very nervous about goods trains messing about on mainlines.

What railway company are you modelling?

If that's the case then I really will have to go back to the drawwing board, as there wouldn't be space for such a thing with the current layout plan. The layout will be late '70's BR, nominally Western Region.

[BluenGreyAnorak]

Damn. Seems to be a problem with attaching images again. Hopefully it'll come back soon.

[BluenGreyAnorak]

Excellent - the images are back and my ideas are now displayed for all to see I should probably mention that these drawings, although created with Xtrkcad, are not to scale - they're just to demonstrate the principles.

[Kenton]

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Horrors - a double reversing maneuver to get into the siding from the down and almost as bad to get back to the down. I don't think that works.

 

Why, other than the slope and space, can't you put in the reception loop/lay by?

[BluenGreyAnorak]

Well, mainly it's just the slope and the space but, notwithstanding that, to be honest I'm not really sure how to make it work. The biggest issue with what I initially proposed seemed to be the facing pointwork on the main line, so how do I get across from the down to a loop without reversing?

[The Stationmaster]

Right one answer to your problem is to make the original slip a diamond (unless you also want a trailing crossover using a trailing slip connection?) and perhaps move (away from the tunnel) the trailing connection you have now added in the Up to get it clear of where the connection comes in from the Down?

 

Both the mainline connections would come into the same yard line, parallel to the running lines, and your 'yard sidings' or whatever would connect off that - just like several places I could name on the 1970s WR .

[Fat Controller]

Right one answer to your problem is to make the original slip a diamond (unless you also want a trailing crossover using a trailing slip connection?) and perhaps move (away from the tunnel) the trailing connection you have now added in the Up to get it clear of where the connection comes in from the Down?

 

Both the mainline connections would come into the same yard line, parallel to the running lines, and your 'yard sidings' or whatever would connect off that - just like several places I could name on the 1970s WR .

Llanelli, Mike?

There were locations with a facing connection off the main line- the exchange sidings for the BP&GV at Burry Port and Pembrey being one. Not far away, at Old Castle Crossing, Llanelli, a facing crossover served both the LMMR branch and the reception sidings from Duport Yard. All these branched off the main line from Swansea to Fishguard. There are a series of books of track diagrams for the WR, shewing (GWR spelling..) the same location at different times, which show how track layouts change. They are well worth seeking out- the author is R A Cook, IIRC.

Brian

[BluenGreyAnorak]

Right one answer to your problem is to make the original slip a diamond (unless you also want a trailing crossover using a trailing slip connection?) and perhaps move (away from the tunnel) the trailing connection you have now added in the Up to get it clear of where the connection comes in from the Down?

 

Both the mainline connections would come into the same yard line, parallel to the running lines, and your 'yard sidings' or whatever would connect off that - just like several places I could name on the 1970s WR .

Would something like this be a reasonable compromise, perhaps?

 

 

That arrangement appeals as I can fit it into the space I have without a major re-design of the rest of the layout.

 

Assuming that's essentially correct, any thoughts on my original query about operating near to the tunnel? A train arriving on the down would be all but completely inside the tunnel to clear the points.

[The Stationmaster]

Would something like this be a reasonable compromise, perhaps?

 

 

That arrangement appeals as I can fit it into the space I have without a major re-design of the rest of the layout.

 

Assuming that's essentially correct, any thoughts on my original query about operating near to the tunnel? A train arriving on the down would be all but completely inside the tunnel to clear the points.

 

That I like - very protypical altho' the short distance between the pooints on the yard line might sometimes not be (but only 'sometimes' ) and doing away with a single slip (to make a trailing crossover) where the diamond is really did happen in some WR rationalisation schemes :icon_thumbsup2:

 

As for shunting in/from the tunnel I don't think it's a problem although it is very likely that in a similar prototype circumstance the length of the train might have been limited for sighting reasons. In essence the ground signal for the trailing connection in the Down line would be in the 6 foot (ie between the two running lines and thus more readily visible from the loco) and there would be a Local Instruction for the Signalman not to clear that signal until the train had been 'accepted' by the yard staff, the train would then setback solely on the authority of that signal until such time as the footplate crew could see someone on the ground to control the last part of the move.

[BluenGreyAnorak]

Excellent! Thanks very much, Mike

[phil-b259]

Ok, bare with me here whilst I make sure I understand this bit: a trailing point on the down and trailing slip on the up would give me access to and from the down to the yard, but no access out onto the up, yes? If so, that's not going to work - I need trains to arrive at the yard on the down from the fiddleyard and return on the up. If everything else works out space-wise, I may also have the option of returning to the fiddleyard by continuing on the down, but that's really an added extra for increased operational interest.

 

I've been mulling this over a bit more and have come up with the following alternative, which I think removes the concerns about facing slips and the like whilst still giving me operational flexibility. Is this likely to be a more acceptable arrangement?

 

 

This arangement certainly was the most common method of acessing goods yards back in the day when vertually every station had one. It minimises the number and complexaity of the pointwork while removing the need for any facing points. The downside from an opperational perspective is that it does obstruct the main lines for quite a long time while manouvering trains in and out of the yard.

 

Would something like this be a reasonable compromise, perhaps?

 

 

That arrangement appeals as I can fit it into the space I have without a major re-design of the rest of the layout.

 

Assuming that's essentially correct, any thoughts on my original query about operating near to the tunnel? A train arriving on the down would be all but completely inside the tunnel to clear the points.

 

This has the advantage of allowing trains to clear the main line quicker than the traditional layout while still only using two points. In modern installations this minimises the cost and complexity of the controlling circuitry compared to a set of single leed connections while retaining the same functionality. One such installation is located at Godstone My link (ironically not that far from a tunnel either, controlled from a set of switches in a lineside cabinet, released from Three Bridges power box.