Track Spacing

[DCB]

I was sorting through some pictures when I found a good pic of a BR1G tender top on 92214 seen from the road bridge at Todington on the Glos Warks rly, and was struck by how close the train on the next line was.

 

The next picture  now attached showed this even more clearly, as did one taken looking the other way, there is barely a couple of feet between trains and this on the GWR.   The picture of the 14XX on WSR shows only a couple of feet clearance, two people could clash heads by looking out of windows as trains passed.

 

I don't know what track spacing you would need in 00 to achieve this but I'm guessing 43mm, I have 42mm in my carriage sidings.   Peco seem to use 50mm for streamline and a vast chasm for set track. Enough to get podgy fingers between tracks to re rail after accidents I think.

 

Just planning to reduce my bed railway track spacing to 43mm on the straights from set track spacing and see how much difference it makes so I thought I would share these pics

[Pete the Elaner]

I did this for my current layout & I think it makes a huge difference. I wrote an article about it for the Double O Gauge Association's regular magazine.

How did you calculate 43mm? I think you have failed to account for OO being 2.4mm too narrow because I made this distance 44.8mm.

I read somewhere that 6' did actually mean 6', not like "the four foot" referring to 4'8½".

 

Here are my calculations (Taken directly from the DOGA article).

 

What we have:
Distance between centres = 16.5mm/2 (half track width) * 2 (because there are 2 tracks) + 2mm (approximate width of 2 running rails) + 32mm (streamline’s 6’ way) = 50.5mm

What I want:
Distance between centres = 4’ 8.5” I’m going to pause here because I can see Imperial is going to be a handful when I need to divide by 76 so I’m going to work in metric. This is 1422mm, which is much easier! I will assume that rail width is roughly accurate.. It looks about 3” (76mm) & for this purpose, it is good enough for me. 6’ is 1829.

Distance between centres = 1422/2 *2 + 76*2 +1829

= 1422 +152 +1829 = 3403

& convert that back to 4mm 3403/76 = 44.8mm

 

It is important to consider the clearance going around curves. Very few of us have layouts with curves as gentle as the real railway & you will run out of clearance very quickly. I was lucky because the curves on my layout are all off-scene.

 

I actually removed 5mm, which brought the spacing down to 45.5mm, so still marginally overscale (0.7mm). I was happy with the difference it made though.

 

 

I have attached a couple of photos to illustrate the difference.

 

 

 

 

[DCB]

I did this for my current layout & I think it makes a huge difference.  

 

I actually removed 5mm, which brought the spacing down to 45.5mm, so still marginally overscale (0.7mm). I was happy with the difference it made though.

 

 

 

 

Great pics, it illustrates just how much more realistic the reduced spacing is, obviously you need more clearance on curves and a lead in  transition curve, my criteria being will a Hornby King on the inside track clear a Mk1 coach on the outer.

There seems to be a dearth of pictures of two trains side by side taken from road bridges, I have read many many books of railway photographs and seen virtually none, so thought I would share mine.

I feel there are an awful lot of layouts hampered visually by over wide spacing, especially small ones.

[Siberian Snooper]

The Cheltenham and Stratford railway was built in the early 1900s and thus is built to standard gauge standards and not broad gauge, these standards are a half inch more on the GW.

[imt]

There is a discussion of this and many other related things on another thread, which you may have missed:

 

http://www.rmweb.co.uk/community/index.php?/topic/106067-passing-loop-clearance/

 

The O Gauge Guild pamphlet reference is particularly interesting for a wider coverage of spacings for such things as roadways in goods yards etc.

 

http://www.gauge0guild.com/manual/07_D7_1_1.pdf

[Pete the Elaner]

Great pics, it illustrates just how much more realistic the reduced spacing is, obviously you need more clearance on curves and a lead in  transition curve, my criteria being will a Hornby King on the inside track clear a Mk1 coach on the outer.

There seems to be a dearth of pictures of two trains side by side taken from road bridges, I have read many many books of railway photographs and seen virtually none, so thought I would share mine.

I feel there are an awful lot of layouts hampered visually by over wide spacing, especially small ones.

I agree but it is something you just get used to in model form.

If you don't want to do end up getting sucked into doing it, scroll away from my photos now.

 

One of the reasons I scrapped my old layout was because I experimented with this after I built it. There were other reasons too.

[Rivercider]

Great pics, it illustrates just how much more realistic the reduced spacing is, obviously you need more clearance on curves and a lead in  transition curve, my criteria being will a Hornby King on the inside track clear a Mk1 coach on the outer.

There seems to be a dearth of pictures of two trains side by side taken from road bridges, I have read many many books of railway photographs and seen virtually none, so thought I would share mine.

I feel there are an awful lot of layouts hampered visually by over wide spacing, especially small ones.

Here is Truro in 1983

50014 Warspite with the 11.05 Penzance - Plymouth, 45128 is heading the Penzance bound service, 8/3/83

 

cheers 

[LNER4479]

I did this for my current layout & I think it makes a huge difference. I wrote an article about it for the Double O Gauge Association's regular magazine.

How did you calculate 43mm? I think you have failed to account for OO being 2.4mm too narrow because I made this distance 44.8mm.

I read somewhere that 6' did actually mean 6', not like "the four foot" referring to 4'8½".

 

Here are my calculations (Taken directly from the DOGA article).

 

What we have:

Distance between centres = 16.5mm/2 (half track width) * 2 (because there are 2 tracks) + 2mm (approximate width of 2 running rails) + 32mm (streamline’s 6’ way) = 50.5mm

What I want:

Distance between centres = 4’ 8.5” I’m going to pause here because I can see Imperial is going to be a handful when I need to divide by 76 so I’m going to work in metric. This is 1422mm, which is much easier! I will assume that rail width is roughly accurate.. It looks about 3” (76mm) & for this purpose, it is good enough for me. 6’ is 1829.

Distance between centres = 1422/2 *2 + 76*2 +1829

= 1422 +152 +1829 = 3403

& convert that back to 4mm 3403/76 = 44.8mm

Whilst I don't disagree with your calculations, it's actually a whole lot easier just to consider the spacing between track centres. The minimum prototype dimension is 11' 2", so a simple piece of 4mm:1foot maths computes a figure of 44.67mm, which is as near as dammit to your 44.8mm.

 

Attached is the standard loading gauge dimensions from 1950 (no idea where I got it from!) which both quotes the 11' 2" figure and the 6' 0" figure. You are correct in that the width of the rail head has to be taken into account. The diagram quotes 2 3/4 " which, when doubled and added to 4' 8 1/2" and 6' 0" gives the 11' 2" figure.

 

I would very much doubt that the dimensions in any of the prototype pictures shown (including GWSR) would be anything other that 11' 2" spacing.

 

From a model perspective, I think adopting scale 11' 2" track spacings (where that is the spacing on the prototype that one's model is based on) makes a huge difference in appearance and is a defining feature of UK railways, compared to just about everywhere else in the world (a legacy of us being the first and not thinking big enough - GWR excepted(!) - in the formative years of the railway age). For simplicity, I use 45mm and reckon that's OK down to about 5 foot radius, below which, time to progressively open out the track centres!

[Compound2632]

Apologies if I missed it but some points that I don't think have been mentioned are that if you use prototypical track centres:

• overbridges etc. can be modelled to scale;
• in pointwork, crossing lengths are shorter for a given crossing angle so you gain some valuable length on your layout - or can trade up to a shallower crossing angle;
• your double track main line takes up less baseboard width so there's more room for scenery or additional sidings.

I think I was also thinking of this parallel thread.

[The Stationmaster]

And here is the proof, should anyone need it, that Peco Streamline was developed with those modelling 'narrowed' former broad gauge lines in mind.  The final picture, albeit with some overhead obstructions really shows the difference between track laid to old broad gauge centres and those 'modern' narrow gauge centres if you look up through the ladder crossovers.  Click on pics to enlarge them.

 

 

 

 

 

[JZ]

In those pictures, the 10ft appears narrower than the 6ft.

[Siberian Snooper]

In those pictures, the 10ft appears narrower than the 6ft.

It's permissable to have 10 ft + 6 ft + 10 ft, usually loops either side of the mains, but not always.

[Pacific231G]

Google Earth is your friend here at least for current practice. Since you know the gauge that gives you a "ruler" for measuring everything else from the lengths of points to the widths of platforms. In some areas where the aerial photos are particularly clear you can even measure the sleeper spacing and point timbering. You obviously need to make some allowance for photographic distortions but measuring the clearances at a number of points should solve that. Clearly, because 00 (and British N) use narrow gauge track with standard gauge vehicle bodies, the spacing between the rails has to be  a bit wider though on straight track presumably the centre to centre distance can at least in theory be the same . 

 

The maximum service speed obviosuly affects the minimum separation for high speed lines because of the aerodynamic effects but how much does that affect the separation on classic main lines? 

[LNER4479]

The maximum service speed obviosuly affects the minimum separation for high speed lines because of the aerodynamic effects but how much does that affect the separation on classic main lines 

I'm not sure it affects it at all. The 6 foot seems good enough for 125mph on the ECML. Can get a bit exciting when two 125mph trains pass - I've known the contents of a drink cup be knocked over with the impact.

 

I doubt very much that the track separation has been increased on Digswell viaduct and Welwyn tunnels since they were built in the 19th Century.

[Pete the Elaner]

I'm not sure it affects it at all. The 6 foot seems good enough for 125mph on the ECML. Can get a bit exciting when two 125mph trains pass - I've known the contents of a drink cup be knocked over with the impact.

 

I doubt very much that the track separation has been increased on Digswell viaduct and Welwyn tunnels since they were built in the 19th Century.

The phrase "classic main lines" later in the posting inferred that "high speed lines" meant modern high speed 140mph+ lines like HS1 not the Kings X-Edinburgh route.

Air resistance increases with the square of the speed so 140mph creates a 25% increase over 125mph for air turbulence which is very significant. Raising the speed to 180mph is over double the trouble of 125.

 

Linslade tunnel down fast on the WCML (a single bore) has a 90mph speed restriction for non-EPS trains for this reason.

[Zomboid]

It's permissable to have 10 ft + 6 ft + 10 ft, usually loops either side of the mains, but not always.

The distances are just names, and the spacing on the ground is usually historic. I remember on my PTS training in about 2006, we stood next to the throat at Waterloo and the instructor asked if anyone could see where the 6 and 10 foots (feet?) were - it was a trick question. Most of Vauxhall to Waterloo has no 10 foots, just a load 6 foots.

[Pacific231G]

The phrase "classic main lines" later in the posting inferred that "high speed lines" meant modern high speed 140mph+ lines like HS1 not the Kings X-Edinburgh route.

Air resistance increases with the square of the speed so 140mph creates a 25% increase over 125mph for air turbulence which is very significant. Raising the speed to 180mph is over double the trouble of 125.

 

Linslade tunnel down fast on the WCML (a single bore) has a 90mph speed restriction for non-EPS trains for this reason.

That is what I meant and I was wondering whether main lines on which 125MPH trains pass have a minimum separation rather wider (possibly only a few centimetres) than the normal minimum.  

[DCB]

I found a picture of the carriage sidings where I squeezed the track down to around 43mm, I would like to pretend its pre ballasting but that was 6 years ago and it still has not been done.

[Clive Mortimore]

Hi All

 

Please remember that all horizontal dimensions need to be increased as the curves become tighter, allowing for end and central overhanging.

 

Below is my redrawing of the 1972 minimum clearances.

 

[The Stationmaster]

That is what I meant and I was wondering whether main lines on which 125MPH trains pass have a minimum separation rather wider (possibly only a few centimetres) than the normal minimum.  

 

I know of some on the Western which were slewed closer together (down to the standard six foot interval) to allow the linespeed to be raised to 100mph and they weren't moved any further apart when the line speed was raised to 125 mph

[LNER4479]

The UK special case in the Infrastructure TSI (7.6.12.3) states:　

'The nominal distance between track centres shall be 3 400 mm on straight track and curved track with a radius of 400 m or greater.'

 

Just done a bit of number crunching and - lo and behold - 3400mm works out as 11' 2" (ie corresponding to the minimum 6 foot spacing).

 

From what I can interpret, this applies for speeds of up to 100mph.

[nswgr1855]

Be careful exactly scaling down track centers. The smaller the scale the more over scale the end pay on our wheel axles. The error is amplified with the overhang of 4-4-0 locomotives, probably the worst offenders.

 

Cheers,

Terry Flynn.