Clearance above rail height.

[81F]

Currently I only have 1 locomotive and 2 coaches in US HO scale which I hope to use (just for fun!) on what would otherwise be my British outline model railway. I am now about to install a couple of tunnel mouths and an over bridge. AS I hope to get a few more US models in the future, I wondered how much clearance I should leave above the top of rail level?

Please note, I would like to keep things as low as possible since I do not want my lower British stock to look to out of place.

[jward]

i recommend 3" minimum from the top of the raail to the underside of the upper level. that said, i often trim my tunnel portals to just clear a high cube boxcar. that would be somewhere around 2 3/4"..... this gives the effect of the tight clearances once common in the east. but the tunnel portals are easy to replace if i ever buy something which won't clear them.

[Doneldon]

81-

There are certain minimum clearances over which you have no control; however, there are thigs over which you can
exercise some control. The main one is the type of bridge you use. Through truss bridges, for example, add almost
nothing below track level and are a good choice when you want the least railhead to railhead distance.

                                                                                                                                                  -- D

[sd24b]

Currently I only have 1 locomotive and 2 coaches in US HO scale which I hope to use (just for fun!) on what would otherwise be my British outline model railway. I am now about to install a couple of tunnel mouths and an over bridge. AS I hope to get a few more US models in the future, I wondered how much clearance I should leave above the top of rail level?

Please note, I would like to keep things as low as possible since I do not want my lower British stock to look to out of place.

3-3.5" min.  4" better  Watch your tunnel portals on curves.    Phil

[Len]

For US prototype modeling standards you might want to check out: http://www.nmra.org/standards/sandrp/consist.html

Clearance info is contained in standard S-7, found at: http://www.nmra.org/standards/sandrp/pdf/s-7_2011_02.pdf

For the 'Classic' era, 1920-1969, the clearance from the top of the rail should be 3-1/32in (77mm). For the modern era the clearance from the railhead would be 3-5/32in (80mm).

Len

[rbryce1]

3-1/32" ........  3-5/32".......  I can see making this now.  Measure it with a micrometer, mark it with a felt tip pen and cut it with a hack saw!  

[Jhanecker2]

A caliper or possibly  an adjustable square might be  a better  measuring tool .  J2.

[jward]

actually the best possible tool is an nmra guage. if it will slip under your overhead trackage you're fine.

no need for fancy measurements.

as a matter of fact, when i am setting the height of my roadbed, i leave the risers closest to the overhead crossing free floating at first, then make final adjustments to clear the guage before permanently fastening them.

trying to measure risers exactly to calculated dimensions is doing things the hard way. it is much easier and quicker to adjust things to suit often imperfect conditions, than it is to calculate what those conditions ideally should be, only to find that your calculations are off because something else wasn't built exactly to specs.

[Len]

NMRA Standard gauges can be ordered directly from the NMRA, and are also available through Walthers. The Walthers mfg-item numbers are:

98-1 HO Standards Gauge
98-8 N Standards Gauge
98-9 On30 Standards Gauge

The 98-5 O Scale Standards Gauge is for 2-Rail Scale O, not 3-Rail 'tinplate' O.

Len

[CNE Runner]

81F (and odd surname...but you did say you model Welsh railways) - I measured my NMRA clearance gauge and got the following: height = 7.5 cm, width = 5.2 cm.

You intend to run some U.S. stock "just for fun" and I intend to to likewise with English stock...'small world isn't it? [PS: E. Hatton's and Railway Modeller have been extremely helpful.]

I was only kidding about your user name (and Wales). Best of luck.

Cheers,
Ray

[Jhanecker2]

Micro-Mark also carrys the NMRA gauge on their website. J2

[rogertra]

81F (and odd surname...but you did say you model Welsh railways) Cheers,
Ray

81F, as anybody who has even the slightest knowledge of Britain's railways will tell you that it's a "shed code". Every single UK locomotive shed had a shed code and all locomotives allocated to that particular shed carried a cast iron "Shed Code Plate" attached to the bottom of the smokebox door with the shed code outlined in white paint.

81F is the shed code for Didcott and the "F" indicates that 81F is a subshed of 81A Old Oak Common, the ex GWR railway shed for Paddington Station, the GWR's terminal in London.  BTW, although in UK parlance OOC was was a locomotive shed, it actually contained four turntables inside the rectangular building with, I believe, entrances to the turntables on all four walls. Well, at least three walls.  It's been around 45 years since I was last there and most of it no longer exists.

In 1948, OOC had around 265 steam locomotives on its allocation.

Yes, it was a big shed but not the UK's biggest.

[81F]

81F (and odd surname...but you did say you model Welsh railways) Cheers,
Ray

81F, as anybody who has even the slightest knowledge of Britain's railways will tell you that it's a "shed code". Every single UK locomotive shed had a shed code and all locomotives allocated to that particular shed carried a cast iron "Shed Code Plate" attached to the bottom of the smokebox door with the shed code outlined in white paint.

81F is the shed code for Didcott and the "F" indicates that 81F is a subshed of 81A Old Oak Common, the ex GWR railway shed for Paddington Station, the GWR's terminal in London.  BTW, although in UK parlance OOC was was a locomotive shed, it actually contained four turntables inside the rectangular building with, I believe, entrances to the turntables on all four walls. Well, at least three walls.  It's been around 45 years since I was last there and most of it no longer exists.

In 1948, OOC had around 265 steam locomotives on its allocation.

Yes, it was a big shed but not the UK's biggest.

Hi,

Your very close Didcot was actually 81E. 81F was the next shed down the line which was the former Great Western Railway shed at Oxford, which is my home town. Oxford actually once had two sheds. The other was on the old LMS line and was a subshed of Bletchley and at nationalization and shared its code of 4A. Sadly nothing is left of either sheds now since the use of locomotives on the British railway system has all but gone (except for freight). Fortunately Didcot still survives as a museum dedicated to preserving various aspects of the former Great Western Railway.

[rogertra]

Shed codes did change over time, my listing showed 81F as Didcott so it's also possibly the  listing I used was out of date.