Track Spacing?

[adamcooke]

Hi there,

 

I'm looking at using PECO Streamline Code 75 track and I'm wondering about track spacing when combined with points with crossovers. With the streamline the centre-to-centre distance is 50mm whereas with the Setrack (and Hornby) it's 67mm. 

 

I don't have many trains yet so I don't have a good enough collection to do some real world tests with different sized trains and engines to determine the best spacing between tracks on various curves.

 

Does anyone have a suggestion on the best size to go for between tracks? I'm not looking at a huge layout here so the trains aren't going to be massive the radius of the curve won't be less than a Hornby 2nd radius (438mm). 

 

I'd prefer the larger gap (67mm) but not quite sure on the best way to achieve this using the Streamline points. Any idea there?

 

Thanks in advance for any tips!

 

Adam

 

 

[loickebros]

Hi there,

 

I'm looking at using PECO Streamline Code 75 track and I'm wondering about track spacing when combined with points with crossovers. With the streamline the centre-to-centre distance is 50mm whereas with the Setrack (and Hornby) it's 67mm. 

 

I don't have many trains yet so I don't have a good enough collection to do some real world tests with different sized trains and engines to determine the best spacing between tracks on various curves.

 

Does anyone have a suggestion on the best size to go for between tracks? I'm not looking at a huge layout here so the trains aren't going to be massive the radius of the curve won't be less than a Hornby 2nd radius (438mm). 

 

I'd prefer the larger gap (67mm) but not quite sure on the best way to achieve this using the Streamline points. Any idea there?

 

Thanks in advance for any tips!

 

Adam

Best way is to use one of these http://durhamtrainsofstanley.co.uk/my_store/index.php?main_page=product_info&cPath=119_120_52&products_id=4890

Dave

[adamcooke]

Best way is to use one of these http://durhamtrainsofstanley.co.uk/my_store/index.php?main_page=product_info&cPath=119_120_52&products_id=4890

Dave

 

What does it do?

[Phil Bullock]

You locate one of the tabs in your track already laid and use the second tab to give you the alignment for the second track. Has both the spacings on there on opposite sides.

 

Push the boat out and buy 2 or 3 to make life even easier!

 

With 2nd radius you will want the 67mm spacing - and even that may not be enough on that severe a curve if you are running modern stock with its large overhangs

 

Phil

[28XX]

Conversely, if you want to model to scale, real railways get as close as 11’ centres, 44mm in 4mm to the foot.

[Phil Bullock]

But perhaps not on ex GWR broad gauge lines....

 

 

Phil

[Compound2632]

With cunning use of the Hornby R628 large radius curve as a "transition curve", it is possible to get closer to the prototypical double-track centres - down to around 48 mm if not 44 mm - whilst preserving 67 mm centres on the curve. Here are a couple of examples (apologies for the lack of dimensions - these were done a long time ago for my own amusement):

 

q track curved loop left.pdfq track curved crossing right.pdf

 

With the crossing-on-the-curve, long carriages - certainly Mk1s - and big engines - especially 4-6-0s and 4-6-2s - may not clear when passing on adjacent lines. This doesn't worry me as I like short carriages and small engines.

 

Combining the R628 curve with either of the "express" points R8077/R8078 also gives track centres around 48 mm.

 

Using closer to prototypical track spacing on the straight means that over-track structures such as bridges can be closer to scale; also you're using up less baseboard width so there's a bit more space for scenery or, if you must, that extra siding.

Edited October 29, 2018 by Compound2632

[ejstubbs]

With all due respect, this topic has been done to death on RMWeb.  Google "track spacing rmweb" (leaving off the quotation marks) to find all the past threads on the subject and fill yer boots...

[Pete the Elaner]

You locate one of the tabs in your track already laid and use the second tab to give you the alignment for the second track. Has both the spacings on there on opposite sides.

 

Push the boat out and buy 2 or 3 to make life even easier!

 

 

A cheap & cheerful tool. My only gripe about them is they fall over when the track is spaced correctly, then potentially allowing the gap to wander. This can be resolved by glueing 2 of these gauges either side of a small strip of wood so they become self-supporting. 

[Pete the Elaner]

With cunning use of the Hornby R628 large radius curve as a "transition curve", it is possible to get closer to the prototypical double-track centres - down to around 48 mm if not 44 mm - whilst preserving 67 mm centres on the curve. Here are a couple of examples (apologies for the lack of dimensions - these were done a long time ago for my own amusement):

 

q track curved loop left.pdfq track curved crossing right.pdf

 

With the crossing-on-the-curve, long carriages - certainly Mk1s - and big engines - especially 4-6-0s and 4-6-2s - may not clear when passing on adjacent lines. This doesn't worry me as I like short carriages and small engines.

 

Combining the R628 curve with either of the "express" points R8077/R8078 also gives track centres around 48 mm.

 

Using closer to prototypical track spacing on the straight means that over-track structures such as bridges can be closer to scale; also you're using up less baseboard width so there's a bit more space for scenery or, if you must, that extra siding.

45mm spacing looks great on straights & very gentle curves.

50mm spacing is a nice compromise & I can see why Peco have chosen this as their streamline standard. I find it intriguing that when a crossover is fitted with insulated rail joiners, these take it slightly wide of this standard.

67mm may be wide but for sharp curves, it should provide adequate clearance. I notice that Mk1s & pacifics have been mentioned. A Mk3 is much more demanding, both inside & outside.

Worst of all for outside overhang is APT-E, so if you are likely to run one of these...beware. The real one had very limited route availability on BR for this reason.

[Phil Bullock]

Cheers Pete

 

The new Hornby 800 is bad too!!!!

 

Phil

[Wheatley]

With all due respect, this topic has been done to death on RMWeb.  

 

Indeed. The short version is that if you use Streamline (50mm) spacing on Setrack (67mm) curves, your coaches will collide with each other on the bends.

[davetheroad]

45mm spacing looks great on straights & very gentle curves.

50mm spacing is a nice compromise & I can see why Peco have chosen this as their streamline standard. I find it intriguing that when a crossover is fitted with insulated rail joiners, these take it slightly wide of this standard.

67mm may be wide but for sharp curves, it should provide adequate clearance. I notice that Mk1s & pacifics have been mentioned. A Mk3 is much more demanding, both inside & outside.

Worst of all for outside overhang is APT-E, so if you are likely to run one of these...beware. The real one had very limited route availability on BR for this reason.

 

Those 50mm centres are just nominal, maybe it should be 50.8mm which is what Shinohara use for their fixed radius curves which go in 2 inch increments up to 36 inches. With my code 100 trackwork I put a small length setrack straight between the points. This gives approx. 60mm track centres which suits me fine and I don't even notice it is too wide, after all, the distance between the rails is too small!. I use setrack curves in the fiddle yard.

 

Adding a setrack ST202 79mm straight takes streamline turnouts to almost setrack distance

Edited October 30, 2018 by davetheroad

[34theletterbetweenB&D]

...I'm looking at using PECO Streamline Code 75 track and I'm wondering about track spacing when combined with points with crossovers. With the streamline the centre-to-centre distance is 50mm whereas with the Setrack (and Hornby) it's 67mm....the radius of the curve won't be less than a Hornby 2nd radius (438mm). 

 

I'd prefer the larger gap (67mm) but not quite sure on the best way to achieve this using the Streamline points...

The question not yet asked: is the entire layout to be made using Streamline code 75?

 

If so then a small piece of flexitrack between the points forming the crossover allows any spacing you require. (An alternative is to use the Streamline spacing on parallel straight tracks, and have the tracks diverge to give the greater spacing on the approach to curves.) Keep in mind also you are not constrained with flexible track to the 'second radius' dimension. If space permits something even slightly larger, go for it.

 

If the plan is to blend set track and Streamline, then abandon all thought of code 75. Use Streamline code 100 to avoid having to deal with a rail height mismatch every time there is a connection between a set track and Streamline piece

[The Johnster]

Your real issue is about the radius of the tightest curves on your layout.  I am a little confused by mention of code 75 (presumably bullhead chaired) Peco track and second radius curves; I would not recommend that you use any flexible track, even the more robust code 100, in such a tight curve and have always regarded 2 feet as the minimum for such track based on something I read in Model Railway Constructor when god was still in short trousers and I was not long out of them.  The purpose of flexi track is to achieve large radius curves on more 'scale' intended layouts, and to be able to include transition curves.  It does not respond well to sharper curvature, and may well 'pop' chairs and pull out of gauge.

 

Very few of us, even those who claim to be attempting to build things to scale, have the space to model the sort of curves that real trains are able to negotiate at high speed.  Even the sort of pointwork you find in yards, where speeds are limited to 15mph, equates to Peco Streamline large radius.  Modelling is a compromise and one of our biggest is track curvature, in order to get a decent layout in the space we have available.

 

Curvature has a direct impact on double or multiple track centres, as clearance must be maintained between the longest stock that can possibly ever pass on the curve.  Depending on the actual stock used, it will overhang outwards at the ends beyond the bogies, and inwards between them to different extents.  The RTR manufacturers recommend minimum radii for longer coaches for this reason, and setrack geometry allows for it if these recommendations are followed.  But setrack track centres are visibly wider than most prototype situations (ex GWR broad gauge lines are an exception) and one would prefer closer spacing to improve the appearance.  That single line BLT is starting to look more attractive now, isn't it...

 

Streamline geometry is a compromise, allowing you to have your straighter sections prototypically close, but bearing in mind that 00 is in any case a compromise gauge which is too narrow, so the visual problem is worsened, you cannot just scale down the distance between the most adjacent rails because, although the track is narrower gauge than it should be and apparently increases the clearance, the stock isn't, and it the stock we are most worried about in the clearance issue.  More than one experienced modeller has been caught out with stock fouling on flexitrack curves because he/she's forgotten to ease the clearances to allow fully for them.  Best to find out this mistake before the track is PVA-ed and ballasted!

 

My advice, IIRC from the same MRC article and therefore probably from Cyril Freezer, who knew what he was talking about, is to lay the track out on the board and lightly pin or very lightly glue it in place, and test run every item of stock over it in every possible permutation.  Take your longest vehicle, and 4 pencils, and sellotape the pencils 1 in the centre of the coach and 1 at the end, on each side, so that when you hand push the coach around the layout the pencil will mark the baseboard.  Leave enough play in the sellotape to pull it up out of the way over pointwork, but otherwise keep it vertical; at all costs avoid it's bending inwards towards the track.  

 

You now have a layout with pencil lines drawn parallel/concentric on each side of each track.  Where they cross, you will have fouling and the stock will hit similar stock on the opposite line.  The thickness of half a pencil equals a safety margin which will avoid contact due to wobbles while running.  If they cross or touch anywhere, relay the track with the clearances eased a bit and try again; when all is well you can use that as the final position of the track and start ballasting and permanently fixing it.  The pencil lines will also show you clearances for lineside structures and platforms.  Cut card formers to shape as patterns for your platforms if you are not going to be building them straight away, as the lines will be obscured by ballast, scenery, and painting.

 

Felt tip pens work just as well.

 

Long coaches are not just a modern feature; the GW used it's broad gauge clearance heritage to build 70 foot coaches as long ago as Edwardian times, and there were 70 foot auto trailers as well.  It also built the Centenary stock and Special Saloon to a width of 9'6", a foot wider than the 'standard' loading gauge.

 

I recommend that very sharp curves of the sort found in industrial or dockside situations be made of setrack pre-made curved sections or hand built; flexible track is not suitable for this purpose.  If you need to take your track up after use and relay it next time, then I would again say that sectional set track is much more robust, and easier to store as well.  Few serious modellers will be in this position, though.

Edited October 30, 2018 by The Johnster

[DCB]

This has been thrashed to death.  There is no hard and fast rule regarding track spacing.  50.8 ish mm works well if you stick with flexi track and code 75 streamline.  It wont curve nicely much tighter than about 2ft radius and most stock will pass at 50mm on a 2ft radius curve. There are exceptions the Hornby Dublo breakdown crane and Triang M7 are really bad.   Set track is horrible, the streamline short Y is much smaller and the 2ft point almost as short as a set track one yet takes up a lot less width.  If you don't have any double track curves than perhaps a smaller spacing like 44 mm looks better, I have gone narrower than this, as long as 2 GWR Hall locos cylinders clear on adjacent lines I am content. 

6ft between tracks plus a track width comes out at 40.5mm

[Pete the Elaner]

 

6ft between tracks plus a track width comes out at 40.5mm

You've fallen into the 00 trap!

40.5mm is a scale foot too narrow because 00 is too narrow. Rolling stock isn't though, so you can't simply add 6' to the gauge to get the correct centre to centre spacing.

I believe the 6' is also measured between the outside of the rail head, so you need to add this too.

 

You need to be measuring track centres, or simply use P4's gauge for calculations, because we already accept this to be correct.

This gives 18.87 + 24 = 42.87, then add 2 rail widths (estimate 1mm per rail) = 44.87mm.