Track centres /spacing

[invicta280]

Greetings all. In the best tradition of Gardeners Question Time I would like to ask the panel what do they consider is an appropriate clearance between two tracks for a 32 mm gauge/ 16mm scale line? The only section of double track planned is in the steam up area and that will be straight track. I've seen it suggested that distance between track centres of 160mm is appropriate.
I'm currently doing the ground work on this section and the track will be laid on lite ags/ cinderblocks/ breezeblocks/ call em what you will. Track will be Peco.
The line will have tightish curves so we won't be running Garretts or other biggies. Thanks for any advice.

[IrishPeter]

6.25" or 160mm should do nicely if you plan to run only smallish NG stock. IIRC the WDLR cross section diagrams recommended 10' between parallel tracks. If you plan on doing a Calthrop you'll need at least 7" or 178mm, which is a shade over 11 feet in 16mm or a shade under 12' in 15mm so that the standard gauge waggons riding piggyback will miss each other. This should be widened suitably on curves as the end and centre throw on a 39' bogie carriage is likely to be considerable. Also, if you are going to have stuff riding piggyback your vertical clearance will need to be about 15 scale feet - 240mm/9.5". Otherwise about 7" is plenty. I have tended to go with about 6.75" because that looks about right both my three foot (15/45) and 2'6" (16/45) gauge stock.

Peter in Va

[invicta280]

Thanks Peter. That's reassuring. I didn't want to get the blocks all level and sitting nicely in their beds of pea gravel only to find they were too close. The steam up area is quite slim so I want the two tracks quite close but the actual distance may be dictated by the pointwork. Maybe I should download a couple of those Peco trackplan point templates!

[IrishPeter]

The Skebawn and Castleknox Tramway Mark 2 is going to be a shelf layout in the basement, and I have had a heck of a job making things fit into a relatively narrow space. I picked up a lot of old Aristocraft "Euro-style" track when the old version of that company was ailing a few years ago, and its centres are set at a shade under 7", and this has kind of dictated the track geometry ever since. It means the tracks are a little widely spaced for the usual 6'6" or 7' wide Irish tramway vehicles, but if I every have a rush of blood to the head and build models of the NCC NG Boat Train carriages then I will have the clearance for them!

Cheers,
Peter in Va

[Big Jim]

7 inch should be plenty except on curves as Peter said.
The rule of thumb is probably that you will need more than you think you will need. Especially in places where you might need to get finger access to stuff.

[invicta280]

Thanks chaps. I will check that the gap is not too narrow for the Peco points by downloading the point templates and putting two together to form a crossover.
The only section of double track will be straight so overhang on the corners should not be an issue.

[Soar Valley Light]

This is an interesting question. All the above answers amount to one thing really - it needs to be wide enough for your largest items of rolling stock to pass each other with enough fresh air between them to avoid physical contact.

In reality consideration also has to be given to people sticking their heads out of windows. It never seems to extend to two people with their heads out, one in each train! On standard gauge railways the gauge edge to gauge edge dimension is nominally six feet six inches. I've spent a lot of time researching Lynton and Barnstaple track from photographic references. As far as I can make out they also used six feet six inches. There are a couple of photos taken out of the 'six foot' side window of trains in loops and the space between the stock seems to confirm this. I'm planning to use this dimension on my own line, although I've not laid a second track anywhere yet and will make some physical trials before fastening anything down when the time comes.

This is all well and good. I don't particularly expect any 'foreign' stock on the CFLR, if visitors are likely on your line then you need to consider the possibility of stock with a larger loading gauge than your own operating over your line. In these circumstances the larger the better would seem to be a sensible approach to track spacing. All the comments in previous posts about making allowance on curves for centre and end throw are very valid and very important. This is a fairly simple calculation and if things are likely to be tight it's worth doing the sums. If you have room to be generous with your clearances then you shouldn't have to worry too much about the maths.

Andrew

[IrishPeter]

6'6" seems to hold true for the Isle of Man Railway too, though the oft quoted dimension is 10' centres. Be that as it may, there is not much clearance when two vehicles with duckets pass one another, as they are 8'6" wide over the lookouts, and so they only clear one another by about a foot. 10' centres would be a little tight for the NCC Ballymena and Larne Boat Train stock, which may be why Sheard did not pursue purchasing them when he acquired CDRJC Railcars 19 & 20, though a more pressing problem, given that they were 50' long would have been the centre throw on some of the tighter curves on the South Line. Anyway "A.M." ruled them out of gauge so they did not get to have a third career on the IOM.

From my point of view I am relatively isolated out here in Virginia, so the chances of anyone turning up to play with L&MVLR stock are slim to non-existent, but they would give me a problem. At roughly 128mm wide they would stand a good chance of clobbering various lineside structures if I go skinny on the clearances! Mind you, if you are planning on using L&MVLR gear you need standard gauge dimensions anyway, plus about a foot extra vertical clearance so you can use the transporters.

Cheers,
Peter in Va

[GTB]

In reality consideration also has to be given to people sticking their heads out of windows. It never seems to extend to two people with their heads out, one in each train!

Interesting, how many passengers a year did they lose?

Luckily for modelling purposes the stations on the VR 2'6" lines had a track spacing of 11'0" centre to centre, leaving space to handle models when needed. The same spacing was used between running lines and between sidings in station yards.

The ng locos were 8' wide and the largest rolling stock used was 6'7" wide over the body. The reason the track spacing was set so far apart was probably to allow trains to pass each other with adequate clearance to prevent any open swing doors from hitting each other. It also left plenty of space for employees to walk between lines of rolling stock in a station yard.

Space at Walhalla was so restricted that the station building had to be built over the adjacent creek as shown in the link, but the yard tracks are at the 11'0" spacing specified in the site drawing.

http://www.starhotel.com.au/index.php?EXP=676

Regards,
Graeme

[Soar Valley Light]

Interesting, how many passengers a year did they lose?

I'm not sure anyone was counting Graeme. Back in those days everyone, including officaldom, seemed far more accepting of 'Darwinian selection'!

A six foot way was normally only found between running lines, a loop coming under this category. Space between running lines and sidings and between most sidings was a minimum of ten foot six inches. This was primarily for the reason you mention of staff access (without invoking Darwinian selection!). This is clearly evident in the pictures of the loops at Pilton on the L&B, where staff would be wandering about shunting stock.

Of course, some sidings would be much wider apart to allow for loading and unloading and for access by road to collect and deliver freight.

When referring to track centres rather than running edge to running edge dimensions, any difference in gauge from one line to another will affect the space (that's why RE to RE can be less confusing. Basically,

Track centres = Re to RE + Gauge.

Apologies if this is over simplistic but I've seen some very clever engineer get in a tangle with this simple fact.

[Michael Bishop]

A bit late in the day, but maybe better late than never (I am a recent member).

In 1898 before the opening the Engineer provided the Board of Trade with details of the Railway he had been responsible for building including: Width of formation 9 feet. The space between the lines is 6 feet 6 inches at passing places and sidings.

Many years ago I acquired a collection of L & B photographs including some stereo views. One of looking north along the tracks at Lynton station building with the goods shed behind (with the cross-over reversed), about 1910, I would say has written on the back in the Manager, Charles Drewett's, ink writing: Lynton Stn - Terminus viewed from up (Barnstaple) end. Then in pencil: At stop block end of Platform road there is 5 ft 9 1/2 between outside heads of rails + two guards vans with outlook require 5 - 6 to clear.

On that basis I make the track centres 8' 0 1/2". Van 23 is 7ft 3 1/2 over the lookouts. Coaches 1, 2, 15-17 are 2" more at 7ft 5 1/2". So, 7" clearance with the brake carriages. Presumably tracks would be more widely spaced on curves.

[MRail]

This snap from FR webcam, Porthmadog gives an indication of spacing.
Should be possible to measure & estimate.
[attachment=0]PmdDLG87180502.jpg[/attachment]