OO Gauge double track centres

[The Stationmaster]

Martin in your various files do you happen to have . measurement for 00/EM track centres for former GWR broad gauge lines (basically meaning those where station platforms are at the original spacing) by any chance.  I have doen a calculation but but 'adjusted' it for 16.5mm gauge so an original source check would be be very helpful.

[martin_wynne]

Martin in your various files do you happen to have . measurement for 00/EM track centres for former GWR broad gauge lines (basically meaning those where station platforms are at the original spacing) by any chance.  I have doen a calculation but but 'adjusted' it for 16.5mm gauge so an original source check would be be very helpful.

 

Hi Mike,

 

I don't understand what adjustments are needed for 00 or EM? The double-track centres and spacing at platforms are governed solely by the width of rolling stock and the clearance needed between vehicles. The track gauge doesn't come into it.

 

You previously discussed this in this topic: http://www.rmweb.co.uk/community/index.php?/topic/23043-width-of-the-six-foot/

 

Sorry I don't have any original files myself, but here is Brunel's drawing for the former Weston Junction station (linked from Wikipedia):

 

 

It is showing 26ft between platform edges (12ft-8in + 8in +12ft-8in), allowing for the central train shed columns.

 

If standard-gauge tracks are slewed against the original platforms, they would need to be 4ft-9in (traditional bullhead standard) from the platform edge to the track centre-line. Subtracting 2 x 4ft-9in from 26ft leaves 16ft-6in track centre-to-centre between the platforms. = 66mm centres in 00, EM and P4, leaving clearance for the central columns.

 

Note that nowhere in this calculation does the track gauge come into it. Not 7ft-0.25in, not 16.5mm, not 18.2mm, not 18.83mm. It is irrelevant.

 

cheers,

 

Martin.

Edited March 13, 2018 by martin_wynne

[The Stationmaster]

Interesting drawing.  Using the standard broad gauge 6ft measure the distance from outer rail edge to outer rail edge on the opposite line would be 20ft 3" based on a rail head width of 1.25" (MacDermott's drawing shows 6ft 2.5" measured over the inside rail edges so assumes that width at the railhead - on the original form of construction).  Using the drawing in MacDermott the original broad gauge track would have had a centre to centre measurement of 20ft 0.25".  In most cases platforms have been altered, in some cases only slightly but more often by the addition of different surface slabs which have very slightly increased the overhang and would reduce clearance between the platform and track which has meant the track has been slewed thus the wider six foot now tends to vary slightly from place to place.

 

Thanks for your calculation, next step is to think quite how I will be using the difference or looking at a fudge of some sort..  (The first fudge being a fake back story to explain how a kine actually built to standard gauge might have been built to the Brunel gauge.)

[roythebus]

when I built the MRC's "New Annington" layout, it was decided to have a nice super elevated curve on the main line in one corner. 6' radius or thereabouts, it looked wonderful, built to 45 mm track centres (fine scale 00). Then we found that we had to relay it because stock hit when passing as the coaches tilted! With the introduction of the Jouef Mk 3 stock, that was even more of a problem. Be warned.

[DCB]

Posted 08 October 2010 - 19:54  Posted by Caledonian

 

The short answer is not to get confused by dimensions because the terms 4 foot; six foot; and 10 foot are simply geographical terms used to refer to the location of something or some-one and not to be taken literally. EG: he was walking in the 6 foot. While the latter is a theoretical minimum it can be narrower - at South Gosforth Station the 6 foot is actually four foot eight and three quarters, due to the combination of a restricted site and an engineer with a wicked sense of humour. Elsewhere it can be very wide indeed and pieces of string come to mind... 

 

Hi Mike,

 

I don't understand what adjustments are needed for 00 or EM? The double-track centres and spacing at platforms are governed solely by the width of rolling stock and the clearance needed between vehicles. The track gauge doesn't come into it.

 

Note that nowhere in this calculation does the track gauge come into it. Not 7ft-0.25in, not 16.5mm, not 18.2mm, not 18.83mm. It is irrelevant.

 

cheers,

 

Martin.

 

The track centres are not physical entities, they are notional. It is much easier to measure actual physical items like rails, in fact you can't measure track centres you have to measure something else and introduce a fiddle factor.   It is dead easy to draw track centres on a fag packet, Templot Sundela board etc but that's just theory.

Incidentally I measured some Peco 00 track at 16.83mm gauge and the rails at 1.1mm

 

when I built the MRC's "New Annington" layout, it was decided to have a nice super elevated curve on the main line in one corner. 6' radius or thereabouts, it looked wonderful, built to 45 mm track centres (fine scale 00). Then we found that we had to relay it because stock hit when passing as the coaches tilted! With the introduction of the Jouef Mk 3 stock, that was even more of a problem. Be warned.

As I keep saying build your tracks so the trains clear.  Ignore the "Experts" who tell you to the second decimal place which dimensions to use and do your own checks. I use an old Hornby tender drive King which has a great overthrow on the front buffer beam and a Triang Mk1 coach, if the King on the inside clears the MK1 on the outside then its fine. If two Triang Halls clear on the straight its fine. I don't run Kings and Mk3 stock together.  If something derails it hits stock on the adjacent track, a bit like the real thing.  I'm surprised at the super elevation issues but its a useful warning.

[gordon s]

"Ignore the experts"......That has to be the daftest thing I've read on here....

 

I'm assuming you've never asked for advice on RMweb then David.

 

From someone who is not an 'expert' but always grateful for their advice.

Edited March 15, 2018 by gordon s

[Pete the Elaner]

"Ignore the experts"......That has two be the daftest thing I've read on here....

 

I'm assuming you've never asked for advice on RMweb then David.

 

From someone who is not an 'expert' but always grateful for their advice.

I have not seen anyone recommend a particular spacing, except to use caution because model railways use much tighter curves than the prototype, so larger spacing is required.

[martin_wynne]

The track centres are not physical entities, they are notional. It is much easier to measure actual physical items like rails

 

Of course it is. But you don't need a fiddle factor. To measure the centre-to-centre dimension accurately, measure from the edge of one rail on one track to the same edge of the same rail on the other track.

 

Martin.

[Compound2632]

Of course it is. But you don't need a fiddle factor. To measure the centre-to-centre dimension accurately, measure from the edge of one rail on one track to the same edge of the same rail on the other track.

 

Martin.

 

That's exactly what I did as a teenager nearly forty years ago laying Peco code 100 streamline and points on the straight. 45 mm no problem. In those days I was trimming the points with a hacksaw; with a Xuron cutter it would be easier. If it was easy then, why is it so hard now?

[DCB]

Of course it is. But you don't need a fiddle factor. To measure the centre-to-centre dimension accurately, measure from the edge of one rail on one track to the same edge of the same rail on the other track

 

Martin.

You are ignoring the fact that accurately measuring from the edge of one rail on one track to the same edge of the same rail on the other track actually on a layout is virtually impossible.  What d you propose using? A 12" ruler?  Add in having to reach over and it becomes totally impossible.  I did some pics on a station built over 40 years ago with Farish track and the spacing appears to be 38mm. The interesting bit is that 2 Triang Chassis wont pass, note the Farish 81XX and Triang Hall both leaning as their cylinders have touched but a pair of Bachmann Panniers pass easily, on a 6 foot actually only a scale 4ft 9" wide. 

[martin_wynne]

 

That's fine if the drivers want to share their sandwiches. The problem is that it doesn't actually represent UK prototype practice, and to anyone familiar with that it looks daft.

 

It's your railway to do as you wish, but suggesting that others should do the same is not fair to beginners. There is enough misinformation propagating around the internet without adding to it.

 

regards,

 

Martin.

[Pete the Elaner]

You are ignoring the fact that accurately measuring from the edge of one rail on one track to the same edge of the same rail on the other track actually on a layout is virtually impossible.  What d you propose using? A 12" ruler?  Add in having to reach over and it becomes totally impossible.

 

I did some pics on a station built over 40 years ago with Farish track and the spacing appears to be 38mm.

Farish track will probably be H0, not 00 & in this instance, the difference is significant. 19mm between rails in H0 scales to 5'5", which is still too small.

 

As for how to measure it: How would you usually measure the 6' when laying track?

I would use a gauge. I have made some with 45mm track centres. Slightly overscale, but some models are too.

[Enterprisingwestern]

You are ignoring the fact that accurately measuring from the edge of one rail on one track to the same edge of the same rail on the other track actually on a layout is virtually impossible.  What d you propose using? A 12" ruler?

 

Erm, Plastikard and file some notches.

Please don't make life difficult.

 

Mike.

[gordon s]

I've restarted modelling in OO gauge and I was wondering what the distance is between double track centres for both straights and curves so I can get a realistic looking double track mainline.  Obviously I'm looking for the distance in model form rather than 1:1 scale     

 

 

Thought it worthwhile going back to the OP's question.  He wasn't asking what is the minimum he can get away with.....

 

The answer as others have already said, if you are using flexi track and hand built pointwork then it is normally 45mm on straight track opening out to 50mm plus depending on the track radius on curves.  As a guide I use 50mm spacing on 36" radius and it works fine.

 

Of course there are other situations where RTR track has different spacings and there it would pay to read the manufacturers spec sheets.

Edited March 16, 2018 by gordon s

[Philou]

@ Martin

 

The tea break and sharing of sandwiches seems to have taken a while, given the cobwebs forming on the funnel of 6412

 

Philip

[Clive Mortimore]

The eleven feet and two and a bit inches dimension is the minimum, and from what I can glean from reading about track one that many PW engineers keep close to. Now the PW geezer for where my layout is based wasn't so stingy on the outlay of materials and spaced the track a foot and a bit wider. I think the Peco team must have measured what he laid because it comes out the same as their track.

 

OK Peco spacing is a tad wide but I can live with it. Many of you will not and will seek methods of improving the look of your track. For those who do all I can say is "Well Done".

[DCB]

Erm, Plastikard and file some notches.

Please don't make life difficult.

 

Mike.

 

My point exactly, you need to make a gauge, and you measure the six foot not the centrelines,  Yours is plasticard mine is a bit of scrap wood or a ruler on its side.

 

 

That's fine if the drivers want to share their sandwiches. The problem is that it doesn't actually represent UK prototype practice, and to anyone familiar with that it looks daft.

 

It's your railway to do as you wish, but suggesting that others should do the same is not fair to beginners. There is enough misinformation propagating around the internet without adding to it.

 

regards,

 

Martin.

I didn't build it, I operate it.  I bring my spacing down to 42mm to squeeze in extra sidings, the photos show that 38mm does not work with outside cylindered locos.  It was posed with a couple of locos from elsewhere on the layout, I missed the cobweb, locos don't pass each other at this location so its not an issue.  The road is a loop and the spacing widens behind the photographer.  If it were a prototype location the ground disc protecting the points would be behind the photographer, its a posed photo to show 38mm is too close 

 

The lower pic shows my test loco and coach on the critical curve on the layout, its 3rd radius on the inside and the King almost grazes the wall.   The bufferbeam is about 8mm wide of the rail edge.  The spacing is the least I can get away with and is about 56 mm  at the bufferbeam as the curve sharpens which pushes the bufferbeam wider for a few inches, coming down to 51mm at the right of the picture.  The upper pic is at the  critical point but you just cannot see any gap as the coach side bulges out at a higher level than the bufferbeam.    The problem is it s in the corner of the room on a 1 in 36 gradient. and you can't get at it to measure anything, in fact I hadn't bothered to measure it until this thread.

There is another lower level line in front of it, a bridge to the left and just out of shot a working signal to take the eye away from the sharp curve, the sharpest on the layout and the one long wheelbase 4 wheelers cannot get round, It is 3rd Radius set track on the inside.   The track spacing on the bridge is 47mm the end shown and 45mm the other and I only noticed when taking measurements for the post

Edited March 18, 2018 by DavidCBroad

[Guest Jack Benson]

An odd question,

 

Just putting together the FY, the sequence of turnouts is sml wye followed by a sml left and right on each exit of the wye with the curve facing inwards. 
 

What should be the resulting nominal centres of the two inner roads, my best guess is 55mm.

 

Thank you and StaySafe

[roythebus1]

what radius?what make of track?

[Colin_McLeod]

On 13/03/2018 at 14:32, martin_wynne said:

Note that nowhere in this calculation does the track gauge come into it. Not 7ft-0.25in, not 16.5mm, not 18.2mm, not 18.83mm. It is irrelevant.

 

You left out 28mm 😀

Or should that be 28.08333 🤣

[Chimer]

2 hours ago, Jack Benson said:

An odd question,

 

Just putting together the FY, the sequence of turnouts is sml wye followed by a sml left and right on each exit of the wye with the curve facing inwards. 
 

What should be the resulting nominal centres of the two inner roads, my best guess is 55mm.

 

Thank you and StaySafe

 

For Peco Streamline 00, i.e. SL-97, SL-91, SL-92, XTrackCad makes it 53.5mm.

[martin_wynne]

deleted

Edited November 2, 2022 by martin_wynne
answering topic title instead of last post - sorry

[Guest Jack Benson]

5 hours ago, roythebus1 said:

what radius?what make of track?

Peco code 75 OO/HO

[newbryford]

13 minutes ago, Jack Benson said:

Peco code 75 OO/HO

 

My storage yard is Peco Code 75 medium radius - track centres are 2"

 

 

[Guest Jack Benson]

The FY on the original Grafenwalde was very compact, the layout was purposely built for exhibiting and everything had to fit on four boards just 4,8m x 76cm in total. As a result cassettes were used but these needed a second operator and the new layout is single operator, home use only but it is 6m long, a further 1,2m which can accommodate a double-ended FY capable of remote control.

At each end of the FY, there is a fan of three turnouts, configured for optimum space. No need for more than four roads.

 

33cm x 17,5cm

The FY roads are a minimum of 91,5cm long, enough for 5 wagons + V100, the total length of FY, not including headshunts is 157,5cm. Easily accommodated by the increased length of the layout. 

 

Thanks to the responses received, the two centre roads will set at 50mm apart.

 

StaySafe

Edited November 3, 2022 by Jack Benson