Medium v. Large Radius Points in Country Terminus

[Harlequin]

Ok... Came up with a design.  Looks like it will be closer to 14 feet.  I'm being conservative and going with only 13.

 

This layout utilizes a large radius at the throat.  The runaround will accommodate four coaches, which I feel is pretty generous.  You really lose space quick.  I'm wondering if I should just nix the engine shed...

 

Anyhow, let me know what you all think.

 

BLT1.jpg

I think 4 coach trains are ambitious for this size of layout. Your run round might fit 4 coaches but they won't all stand alongside the platform at the moment and they won't fit into the fiddle yard. (It looks like only two coaches can stand at the platform.)

Is the fiddle yard accessible behind the military sidings and it's backscene? (Thinking about the practicality of reaching over/into it to move rolling stock.)

The goods sidings could be longer by pushing the points to the right. The spacing between the goods sidings (and between the sidings and the other lines) should be adjusted to be a workable yard.

If you have an engine shed (entirely reasonable) you need to think about where locos would be coaled and watered.

The points in the military sidings should be the other way up to avoid the wiggle on entry to the lower siding and make both longer.

You might consider using curves and angles to give the station a bit more character - it's very "square" at the moment.

 

Hope that helps.

Edited July 16, 2018 by Harlequin

[Zomboid]

Having a run round much longer than any train that uses it is no bad thing, many stations were like that and it'll make it feel more spacious when a train is in.

Edited July 16, 2018 by Zomboid

[Chimer]

I think 4 coach trains are ambitious for this size of layout. Your run round might fit 4 coaches but they won't all stand alongside the platform at the moment and they won't fit into the fiddle yard. (It looks like only two coaches can stand at the platform.)

 

 

Don't really agree with this point.  The FY tracks can obviously be longer than shown (I reckon that's just a standard 3-foot length, for convenience, shown on each siding on the last plan).  And with a loco tight to the buffers there's room for 4 coaches in the platform - then set back the empty coaches into the loop, run round, and set back to the buffers before passengers embark.  Which is not to say 3 coaches might not look better …….

 

I also note that if the gate protecting the military sidings goes somewhere near the "M" of Military, the approach track will happily double as the goods yard headshunt.

 

Cheers

 

Chris

[Harlequin]

Don't really agree with this point.  The FY tracks can obviously be longer than shown (I reckon that's just a standard 3-foot length, for convenience, shown on each siding on the last plan).  And with a loco tight to the buffers there's room for 4 coaches in the platform - then set back the empty coaches into the loop, run round, and set back to the buffers before passengers embark.  Which is not to say 3 coaches might not look better …….

 

I also note that if the gate protecting the military sidings goes somewhere near the "M" of Military, the approach track will happily double as the goods yard headshunt.

 

Cheers

 

Chris

I also assumed that the fiddle yard sidings continued to the edge of the baseboard but I estimated that a loco hauling 4 coaches (of average length) would leave the last coach fouling the points. If you removed the loco then 4 coaches might fit but it's a bit of a faff to have to do that every time.

 

Similarly, with coaches having to be set back before you can run round them. (And I think this would have been an unusual procedure in the prototype, wouldn't it?)

[Seanem44]

The fiddle yard shown in what I drafted up is just a placeholder.  The tracks will go all the way to the end, and I am not sure of configuration yet.  I think having the military sidings eliminates the possibility of a traverser.  One of my concerns is indeed uncoupling over a scenic break that will cover up the fiddle yard.  The only other option I have with the allotted space I have would be to turn this in to an L shape layout and make a very thin (one foot) fiddle yard on the wall perpendicular to it. 

 

This option might not be that bad, and would allow for a slightly larger station and bit of a scenic run before entering, but I really need to decide how cramped that will make my man cave.  Or, I keep begging my wife for the 20 foot wall in our basement on the grounds that a layout in the main room would be "decorative".

 

I think I have the foundation for a decent layout though, and can definitely work on curved points, etc, to make the layout flow better.

 

If I can utilize the other wall, I can push the siding and engine shed to the right past the throat of the station.  This will allow me to extend the platforms out so that a full four coaches can be accommodated.  It will also allow for a longer engine shed siding which can fit coal and a water tower much easier. 

Edited July 16, 2018 by Seanem44

[unravelled]

Sorry if it has been suggested, but have you thought about using a combination of medium and large points  in the loco release crossover? A medium radius in the platform road would often be partially concealed, and the more visible large radius point might help give the impression of space. The platform road would be maximised, with a slight loss of length in the loop.

 

Thanks

 

Dave

[wagonman]

Sorry if it has been suggested, but have you thought about using a combination of medium and large points  in the loco release crossover? A medium radius in the platform road would often be partially concealed, and the more visible large radius point might help give the impression of space. The platform road would be maximised, with a slight loss of length in the loop.

 

Thanks

 

Dave

 

 

I don't think the geometry would work and any way why bother when it makes the loop shorter?

[PatB]

All Peco points (barring the code  83 US stuff), AFAIK, have the same angle of divergence at the ends of the tracks and so will join up in any combination of large, medium or small to make a crossover between two parallel tracks at Peco's standard track centres.

[wagonman]

I've just done a quick, and very rough, sketch of how this scheme could work. Large radius points for the station throat and access to the military sidings – the most visible bits – and medium for everything else; could at a pinch use small radius for the military sidings and access to the coal/mileage siding.

 

The loop and the engine shed road would need trap points. Coal and water would be next to the shed – there are several GWR examples of the two combined. The signal box would be at/on the end of the platform like at Bodmin but reversed. The 'milk dock' or end-loading ramp at the other end of the station is modelled on Calne, again reversed.

 

The main problem seems to be disguising the exit to the fiddle/staging yard. A secondary problem is the operation of said fiddle/staging yard. Given the space constraints I would think cassettes would be good – but they do need good clear access. And somewhere to store the spare cassettes!

 

I'm bemused by all this talk of 4-coach trains when we all know the standard fare for a GWR branch was the B-set – two non-corridor brake composites permanently coupled together. Model available from whoever has the old Airfix moulds. Tail traffic could be milk and/or horses. The 6-wheeled siphons were still in general use in 1940ish. We don't have a cattle dock but cattle etc can be loaded/unloaded just using portable fences, or a bloke with a stick. At Calne, which was right next door to a bacon factory, the pigs were unloaded onto the bank and herded straight to their doom without benefit of any pens or other containment.

 

 

[wagonman]

All Peco points (barring the code  83 US stuff), AFAIK, have the same angle of divergence at the ends of the tracks and so will join up in any combination of large, medium or small to make a crossover between two parallel tracks at Peco's standard track centres.

 

 

I admit I have no knowledge of Peco track but I am bemused by the idea that different radius points – which must surely have different crossing angles – can have the same angle of divergence. Have they rewritten the laws of geometry?

[Zomboid]

They've included various lengths of straight in them to get the track centres to align. It certainly all works in anyrail (though I've used the code 83 for my layout, which doesn't work in the same way at all...).

[Chimer]

The turnout angle is 12^o and the lateral displacement the same whatever the radius of the point.  So the different radii just means the points are different lengths.  It works!

[The Johnster]

If your branch has military traffic it may well feature occasional troop specials as well, and these could well load to 4 bogies; I see no harm in this so long as the normal service does not cramp the site to the same extent.  They could also justify rakes of 'foreign' stock.  

[wagonman]

If your branch has military traffic it may well feature occasional troop specials as well, and these could well load to 4 bogies; I see no harm in this so long as the normal service does not cramp the site to the same extent.  They could also justify rakes of 'foreign' stock.  

 

 

This seems  more like an ammo dump or suchlike. Tidworth, which of course was purpose built for military traffic, had a very long platform (and loop) for troop trains and another, barely half the length, for civvy traffic. I'd have thought by the 1940s troops would have detrained at a suitable mainline station and travelled on by truck. I've not drawn anything to scale but I'd assume 4 bogies would just about fit in the loop – if not the platform. I dare say squaddies could jump 4 feet down to the ground even if their officers couldn't...

[wagonman]

The turnout angle is 12^o and the lateral displacement the same whatever the radius of the point.  So the different radii just means the points are different lengths.  It works!

 

So, even less like the real thing, then...   

[Seanem44]

So interestingly enough, as I was looking up Tidworth, I came upon Lambourn which I had never heard of, and despite different locations of the Engine Shed... the Station is almost the spitting image (sans military yard) of what I drew up....

 

Edited July 16, 2018 by Seanem44

[bike2steam]

A nice prototype, I can recommend the two books by Kevin Robertson, the first book published by Wild Swan has been out a long time, the second more recently.

Edited July 16, 2018 by bike2steam

[wagonman]

So interestingly enough, as I was looking up Tidworth, I came upon Lambourn which I had never heard of, and despite different locations of the Engine Shed... the Station is almost the spitting image (sans military yard) of what I drew up....

 

1911-Lambourn-track-plan.jpg

 

 

The original version – before the GWR rebuilt it – was even closer...

[Pacific231G]

All Peco points (barring the code  83 US stuff), AFAIK, have the same angle of divergence at the ends of the tracks and so will join up in any combination of large, medium or small to make a crossover between two parallel tracks at Peco's standard track centres.

That's true but a crossover with different length points would be pretty unusual because there'd be no point in building it that way; the speed and the stock that could use it would be limited by the sharpest crossing.

The catch with Peco's large radius points IMHO is that the larger radius requires a longer crossing (about 10 degrees I think) so, in order to get to the same final12 degree divergence angle, the curve continues beyond the crossing. That's not unprototypical per se for a single turnout but a crossover would normally be straight between the crossings to avoid an immediate reverse curve. (Peco didn't have that problem with their smaller radius points as, within limits, you can make a turnout shorter for a given crossing angle by using a different set of curves between the ends of the switch blades and the crossing). 

 

With a straight crossover that immediate reverse curve sacrifices some of the advantages of the larger radius. I don't know how much surgery it would require on a pair of Peco long radius points to turn them into a more normal crossover withot wrecking them. You'd have to straighten the diverging V rail and part of the diverging stock rail. You'd probably also want to shorten them to achieve a more credible "six foot" 

Edited July 17, 2018 by Pacific231G

[Joseph_Pestell]

I admit I have no knowledge of Peco track but I am bemused by the idea that different radius points – which must surely have different crossing angles – can have the same angle of divergence. Have they rewritten the laws of geometry?

 

No so much rewritten them as ignored them. See numerous posts on this subject in Peco threads.

 

It's really a very clever answer to a non-existent question. Their Code 80 N gauge range looks so much better without these tricks.

[Seanem44]

The original version – before the GWR rebuilt it – was even closer...

 

I'll have to see if I can find the plan for it somewhere. EDIT... found it.

 

Yeah, I see the carriage sheds there.  Interesting.

 

So here is the question now. 

 

Do I omit the engine shed or keep it?  It seems like a lot of the Engine Sheds on small BLTs were largely being removed by the 40s.

Edited July 17, 2018 by Seanem44

[Pacific231G]

So interestingly enough, as I was looking up Tidworth, I came upon Lambourn which I had never heard of, and despite different locations of the Engine Shed... the Station is almost the spitting image (sans military yard) of what I drew up....

 

1911-Lambourn-track-plan.jpg

Lambourn was a pretty spacious terminus and, of course, had some particularly interesting traffic (though any horses being transported during the war were presumably not racehorses- did horse racing happen during the war?) .

It occurs to me that you could have the loco shed in the same position as at Lambourn but without the second loop so the trap point nearest the terminus end would become the access points for the loco shed. That would avoid the loco shed access shortening the platform. I like the overall curve through Lambourn and the branch did of course have a lot of military traffic- about 100 movements a year-  though only to Welford Park (private branch to RAF Welford) which kept part of it open till 1970 after the rest of the branch had closed in 1960; well before Beeching!

[Harlequin]

That's true but a crossover with different length points would be pretty unusual because there'd be no point in building it that way; the speed and the stock that could use it would be limited by the sharpest crossing.

The catch with Peco's large radius points IMHO is that the larger radius requires a longer crossing (about 10 degrees I think) so, in order to get to the same final12 degree divergence angle, the curve continues beyond the crossing. That's not unprototypical per se for a single turnout but a crossover would normally be straight between the crossings to avoid an immediate reverse curve. (Peco didn't have that problem with their smaller radius points as, within limits, you can make a turnout shorter for a given crossing angle by using a different set of curves between the ends of the switch blades and the crossing). 

 

With a straight crossover that immediate reverse curve sacrifices some of the advantages of the larger radius. I don't know how much surgery it would require on a pair of Peco long radius points to turn them into a more normal crossover withot wrecking them. You'd have to straighten the diverging V rail and part of the diverging stock rail. You'd probably also want to shorten them to achieve a more credible "six foot" 

Even the short straight sections in Small and Medium Radius Streamline points won't be long enough to prevent an effective reverse curve for anything but the very shortest vehicles. Unless the straight section in the crossover is as long as the longest bogie-centre-to-bogie-centre which will run over it (which would be a very long crossover) a reverse curve is inevitable, isn't it?

 

I'll have to see if I can find the plan for it somewhere.

See if you can get Paul Karau's book, "Great Western Branch Line Termini, Volume 1" or the combined Vol 1 and Vol 2 edition.

 

The combined edition covers:

• Abbotsbury
• Ashburton
• Fairford
• Hemyock
• Lambourn
• Moretonhampstead
• Princetown
• Tetbury
• Wallingford
• Watlington

Lots of plans, showing changes over time, and great photos.

Edited July 17, 2018 by Harlequin

[Seanem44]

Lambourn was a pretty spacious terminus and, of course, had some particularly interesting traffic (though any horses being transported during the war were presumably not racehorses- did horse racing happen during the war?) .

It occurs to me that you could have the loco shed in the same position as at Lambourn but without the second loop so the trap point nearest the terminus end would become the access points for the loco shed. That would avoid the loco shed access shortening the platform. I like the overall curve through Lambourn and the branch did of course have a lot of military traffic- about 100 movements a year-  though only to Welford Park (private branch to RAF Welford) which kept part of it open till 1970 after the rest of the branch had closed in 1960; well before Beeching!

I believe I read that the racing continued through the war, but it dwindled.

 

So to understand what you are saying... the terminus end trap point would essentially become the runaround, and the shed would be on siding next to it?  It doesn't appear the engine shed lasted too long.  In reading up on it and viewing photos, it looks like it was gone by the 30s.  I might omit the shed all together.

 

Obviously I would not want to copy the exact prototype, but having a layout grounded in prototype is always nice.  And Welford Park can easily become something else.  I think I might have come up with my plan, which has been done for me

 

It's unfortunate that my Castle will not fit in to the scheme.  Love the engine, but its just not appropriate.  Though I could make up a "needs of the war effort" and "the branch can support its weight" backstory.  I guess since its my layout I can run whatever, right? 

 

Now I just need to take this and adapt it so that it fits my space

 

The fun begins.

Edited July 17, 2018 by Seanem44

[Joseph_Pestell]

 

 

Similarly, with coaches having to be set back before you can run round them. (And I think this would have been an unusual procedure in the prototype, wouldn't it?)

 

I think that it was avoided where possible, even if it meant passengers having a rather longer walk to the exit. But there were some stations laid out in such a way that coaches had to be set back before a locomotive could run round.