Station Crossover clearance

[Tomathee]

Evening, apologies if this has been asked but I couldn't find anything in search using what I thought was correct terminology. 

 

I'm planning my station area and one idea includes a crossover for a loco to run around, using the empty platform opposite as part of a terminus. I only have small radius points spare to play with alongside paper templates and it seems that in using these the front of the loco swings out too far and contacts the platform edge. For the time being I'm sticking to arrow straight platforms for the majority of the length and streamline track spacing, the gap from coach to platform I've done by sight to something that seems reasonable, though if there's a scientific way of measuring I might find I'm too close and solve the problem that way. I figured this is a situation not too unique that nobody will have encountered it and wondered if medium radius offers enough to avoid this or if I'll have to go up to large, not a problem in space but from arranging paper it seems they take up a relatively long length of the station.

 

Many thanks

[r12477]

While the best measure will however be that from your own stock on your layout much as you have described, I have been using the attached document which provides general clearance requirements between track and surrounding structures for different scales.

Scale Guides.pdf

[Joseph_Pestell]

6 hours ago, Tomathee said:

Evening, apologies if this has been asked but I couldn't find anything in search using what I thought was correct terminology. 

 

I'm planning my station area and one idea includes a crossover for a loco to run around, using the empty platform opposite as part of a terminus. I only have small radius points spare to play with alongside paper templates and it seems that in using these the front of the loco swings out too far and contacts the platform edge. For the time being I'm sticking to arrow straight platforms for the majority of the length and streamline track spacing, the gap from coach to platform I've done by sight to something that seems reasonable, though if there's a scientific way of measuring I might find I'm too close and solve the problem that way. I figured this is a situation not too unique that nobody will have encountered it and wondered if medium radius offers enough to avoid this or if I'll have to go up to large, not a problem in space but from arranging paper it seems they take up a relatively long length of the station.

 

Many thanks

 

Not a completely unknown situation on the full-size railway. Some platforms had to have a bit of a notch in the coping stones.

[unravelled]

Here is an example from Banbury in 2014, still present after the track has gone.

 

 

The modelling problem is that throwovers, whatever the peco point radius, will be greater, so the cutout will have to be bigger than scale . One possible compromise would be to increase the whole platform clearance, bringing the cutout back to a more scale appearance.

 

Dave

 

[DCB]

You say Small Radius points. Is that typical Peco Streamline as in 2ft radius in OO or is it the Set Track?

Set track is absolutely hopeless unless you cut great lumps off with a hacksaw.

The 2ft isn't as good as mediums but the trick is to find your worst loco, mine is a Hornby Tender drive King class and just try it and fiddle the patforms to suit, grind bits off with a dremel if you ave to but don't make clearance for moves you will never make.  The King needs clearance to back out but not to swing across forwards and it swings a lot wider forwards so the left hand platform going in is the crucial one.

As we saw last week on the Yorkshire Steam Railway the clearance on the real thing can be pretty minimal.   Conversely 0-4-4Tanks like the Triang M7 and 2-6-4T tanks swing their bunkers wide so its the right hand platform going in which is crucial.   But don't make clearance for moves you never need to make

Many model platforms are too high. 3ft, 12mm above rail level is the absolute limit, not a target.   Buffers are a fraction under 3ft 6" or 14mm.   Some locos have chunks cut out of the buffer beam lower corners to clear.

The widest bits of many locos are exactly at that 3ft platform height so lowering the platform a mm can make a substantial difference. Its a big step up into coaches, not level.   But basically if you have 0.5mm clearance at a terminus that should be fine.

 

Edited March 10, 2020 by DavidCBroad

[The Johnster]

Lowering the platform might help, and, if the platform is behind the train from the normal viewing angle, will create the illusion of it being longer and wider than it actually is.  This can sometimes be enhanced by the platform being on a very gentle curve. Of course any such platform has to be scratch built. 

[Philou]

Don't forget the old trick of tracing out any potential overhangs (loco or modern passenger stock) with a pencil on any outer corner which will give you the general feel of what to expect. The pencil trick can also be used for any overhangs on the inside of curves by placing the pencil at the inside mid-point of your longest loco/wagon/coach.

 

@The Johnster will put me right - as I understand it, GWR steam locos were a little wider than most across the pistons - not just the Kings.

 

Cheers,

 

Philip

[Gwiwer]

A cut-out, bay or notch in the platform was perfectly normal to allow for locomotive swing when using a crossover or loco-release road.  They existed at larger stations and everywhere right down to tiny halts.  Warblington, built from SR "Exmouth Junction" concrete slabs, had cut-outs in both platforms when it had a crossover mid-way along their short length.  

 

By all means use a cut-out and represent it in model form.  I did.  

[The Johnster]

They were, partly because a good bit of the GW’s main line mileage was on broad gauge formations that gave extra width to the loading gauge.  When later routes, such as the cut offs, were built, this was taken into account, and post grouping other routes such as the Cambrian were brought into line, literally.  Some GW coaching stock was 9’ wide, 6” more than the normal restriction and unable to work off region except to the GC London extension. 
 

Locos were restricted by width across cylinders, and the main problem was them attacking platform edges particularly on curves.   

[TheSignalEngineer]

50 minutes ago, Gwiwer said:

A cut-out, bay or notch in the platform was perfectly normal to allow for locomotive swing when using a crossover or loco-release road.  They existed at larger stations and everywhere right down to tiny halts.  

Birmingham Snow Hill had them at the scissors crossovers in the middle of the main platforms.

[melmerby]

2 hours ago, Philou said:

 

 

@The Johnster will put me right - as I understand it, GWR steam locos were a little wider than most across the pistons - not just the Kings.

 

Cheers,

 

Philip

GWR didn't have scalloped buffer plank edges and that is a part most likely to foul at the front when going through a curve.

The Kings would have the most throw-out because of their length.

 

Edited March 9, 2020 by melmerby

[Tomathee]

Thanks very much for all the replies, I left some thanks earlier planning to come back and write a reply when I had the ease of a PC and there's been a few more since.

 

Good picture @r12477, wouldn't have realised that was the reason behind it.

 

@DavidCBroad it was small radius streamline, all I had spare (discounting set track). Next time I have a play around I'll see what moving up to medium with the paper templates would do in terms of pushing the overall length as it's a bit of a tight spot. Also found similar to you with a loco being worse going one way over the other. 

 

@The Johnster I had been thinking particularly with this side I want to get placed first, when there's a train in it will block most of the view and unless you're standing helicopter view a slightly bigger gap would probably go unnoticed. 

 

Thanks again, I will update once I've made some progress

[melmerby]

5 hours ago, The Johnster said:

.  Some GW coaching stock was 9’ wide, 6” more than the normal restriction and unable to work off region except to the GC London extension. 
 

Some GWR coaches were 9' 7" wide and 70' long and couldn't work on many of the GWR's own routes!

 

If you want big, check out the BR class 165 DMU: the bodies are 9' 3 " wide by 74' 6½"/ 75' 2" long.

Edited March 9, 2020 by melmerby

[DCB]

Duplicate

Edited March 10, 2020 by DavidCBroad

[DCB]

On 05/03/2020 at 09:18, unravelled said:

Here is an example from Banbury in 2014, still present after the track has gone.

 

 

The modelling problem is that throwovers, whatever the peco point radius, will be greater, so the cutout will have to be bigger than scale . One possible compromise would be to increase the whole platform clearance, bringing the cutout back to a more scale appearance.

 

Dave

 

I reckon that unit is overhanging the platform.  As long as the overhang is 3ftb 3" or so high it can overlap the platform with no problems.

 

Melmerby.

Some GW stock was 70 ft long and some was 9ft 7" wide,   Super Saloons and Centenaries were 9ft 7" wide . Maybe 40 coaches in total. . They didn't actually do both. I believe the centre overhang was broadly similar.

Los of older pre WW1 GW Coaches were 70 ft long,  while other railways struggled to get beyond 57ft  and were some of the most efficient coaches around for tare weight vs passengers carried. 

 

[Harlequin]

2 hours ago, DavidCBroad said:

I reckon that unit is overhanging the platform.  As long as the overhang is 3ftb 3" or so high it can overlap the platform with no problems.

 

Melmerby.

Some GW stock was 70 ft long and some was 9ft 7" wide,   Super Saloons and Centenaries were 9ft 7" wide . Maybe 40 coaches in total. . They didn't actually do both. I believe the centre overhang was broadly similar.

Los of older pre WW1 GW Coaches were 70 ft long,  while other railways struggled to get beyond 57ft  and were some of the most efficient coaches around for tare weight vs passengers carried. 

 

Dreadnoughts, 1904 onwards: 70ft long 9ft 6in wide. Fair enough, not the 9ft 7in quoted but very close and my books say that was the maximum possible within the loading gauge. They had inset end doors to reduce the effect of the outswing.

Edited March 10, 2020 by Harlequin

[melmerby]

3 hours ago, Harlequin said:

Dreadnoughts, 1904 onwards: 70ft long 9ft 6in wide. Fair enough, not the 9ft 7in quoted but very close and my books say that was the maximum possible within the loading gauge. They had inset end doors to reduce the effect of the outswing.

I've got the two lots of H11 compo diner shown as 70' x 9' 6¾" (but only 4 vehicles in total)

[34theletterbetweenB&D]

11 hours ago, Tomathee said:

...Next time I have a play around I'll see what moving up to medium with the paper templates would do in terms of pushing the overall length as it's a bit of a tight spot. Also found similar to you with a loco being worse going one way over the other...

If a loco will go one way, then it will go the other way, even if there is contact. (A modern solution might be a  little silicone tape on the platform edge where contact occurs.) The better method is to make the leading bogie actually do some work: wheelsets with no lateral slack in the bogie frame and a centering spring action to pull over the front overhang.

Edited March 10, 2020 by 34theletterbetweenB&D
to actually add the content intended...

[The Stationmaster]

5 hours ago, Harlequin said:

Dreadnoughts, 1904 onwards: 70ft long 9ft 6in wide. Fair enough, not the 9ft 7in quoted but very close and my books say that was the maximum possible within the loading gauge. They had inset end doors to reduce the effect of the outswing.

9ft 7" is correct according to GWR publications - that actual width dimension would probably have been 9ft 5.75" wide over body, 9ft 7" wide over handles.  However until 1952 the regularly quoted figure for some stock varied with, in some cases, both width dimensions quoted in publications but not painted on the vehicle.  But following a slight 'coming together of projections' on passing vehicles the dimensions painted on the vehicle solebar were amended from May 1952 to quote both off the width dimensions.  Some earlier figures seem to have varied in respect of which width they quoted as did length figures -  which in some cases were clearly length over buffers rather than over body.