Author Topic: Platform height & wide locos  (Read 923 times)

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Northshorer

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Platform height & wide locos
« on: February 26, 2018, 07:13:42 AM »
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I'm wanting to build platforms on my Chicago Metra station module. According to the Metra handbook platform height is 8" (scale 1.27mm) above rail height. What I'd like help with is whether this will be low enough not to be fouled by wide locos, and I'm thinking of steam locos here in particular with cylinder boxes sticking out.  I want to permanently fix down the platforms so I need to know in advance of any problems that might occur!

As all my stock is modern diesel, I'd be grateful if anyone can measure up their 'wide locos' to see if there would be any clearance issues.
Any help/advice gratefully received

David Milburn
(North Yorkshire, UK) 

https://yagngs.wixsite.com/yorkshire-area-group


peteski

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Re: Platform height & wide locos
« Reply #1 on: February 26, 2018, 07:20:36 AM »
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How far away from the rail head is it located?  That will make a difference too.
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Lemosteam

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Re: Platform height & wide locos
« Reply #2 on: February 26, 2018, 07:25:56 AM »
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8" above the rail is 0.05" in N Scale.

If I recall the Bachmann K4 cylinders are about as wide as they get at 0.866" across, or 0.433" from the centerline of the track.  Not sure how high they are above the rail, although this looks like they would clear 0.05":


« Last Edit: February 26, 2018, 08:05:05 AM by Lemosteam »

Northshorer

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Re: Platform height & wide locos
« Reply #3 on: February 26, 2018, 08:10:46 AM »
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I want to butt the platform edge up to the base of the track. Using Peco Code 55 track it is 0.638" (8.1mm) from the track centre

David

Northshorer

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Re: Platform height & wide locos
« Reply #4 on: February 26, 2018, 08:12:19 AM »
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Sorry,my maths! 0.319" from the track centre

Maletrain

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Re: Platform height & wide locos
« Reply #5 on: February 26, 2018, 10:12:50 AM »
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I don't have the Metra handbook, so I looked at the B&O "Standard Plan" book that I have and see that the platform edge for that railroad is specified as being 30" from the inside of the near railhead.  That is 0.1875" on an N scale model.  If your model track is narrower than twice that (0.375"), then putting your platform right to the edge of the ties would make it too close for even fine scale appearance.  (I don't know how wide your ties are, but the prototype ties stop significantly short of the platform edge, of course.)

And, the B&O platforms were only 4" above the railheads, not the 8" you say Metra specifies.

That said, many locomotive models need more than fine scale clearances. Steam engines, in particular, have things like rods that stick out farther than scale, and come down low on the bottom of their travel as the wheels turn.  I don't know how to deal with that without actually measuring what you intend to run to see what it really needs.  (Or, making the platform clearance pretty large, which seems like what you are trying to avoid.)

My suggestion would be to post a list of the steam engines you think you will want to run (but apparently don't have to measure for yourself), and ask others here that have those locos to check the clearance requirement for you (assuming a clear platform above 8 scale inches over the rail height).

Lemosteam

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Re: Platform height & wide locos
« Reply #6 on: February 26, 2018, 10:30:07 AM »
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I also assumed that the platform is not on a curve, which would also create a dynamic situation that measurement of the model would not predict.

Maletrain

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Re: Platform height & wide locos
« Reply #7 on: February 26, 2018, 11:03:58 AM »
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I see that you posted that your track (tie) edge is 0.638" from the track center.  Since gauge is 9 mm, that puts the tie edge 0.142" from the gauge line (inside of the near railhead).  That is substantially (~3/64") closer than the 0.1875" that scales from the B&O clearance specifications for their lower platforms.

What does Metra say about distance from gauge line to platform?  You should use at least that to make it look reasonably realistic. B&O typically had about a foot between the ends of the ties and the edge of the platform.

Northshorer

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Re: Platform height & wide locos
« Reply #8 on: February 26, 2018, 11:20:25 AM »
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Metra minimum tangent distance from adjacent track centerline to platform edge is 5ft 6"(0.412"...10.5mm)

Problem is I have no idea what will run, as we operate as part of a 'Freemo' style setup with other groups, so literally anything can run (which is why I would like to find the 'worst-case scenario'!)

David

thomasjmdavis

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Re: Platform height & wide locos
« Reply #9 on: February 26, 2018, 11:55:11 AM »
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I am old fashioned, but my inclination would be to go with the width spec'ed by the NMRA standards gauge for platforms (11mm from track center in N scale).   If some equipment does not operate within NMRA specs for clearances, it will probably foul other things in addition to your platforms.   
https://www.nmra.org/sites/default/files/standards/sandrp/pdf/s-7_2012.02.pdf

Tom D.

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thomasjmdavis

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Re: Platform height & wide locos
« Reply #10 on: February 26, 2018, 11:59:31 AM »
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Just realized that the OP is in the UK- so a different standards gauge may apply if members of the group will be operating European or UK equipment- given that while all will be N gauge, it will not necessarily be US N scale (1/160) and may include 1/144 or other ratios.  I would go with whichever standard is largest if UK or Euro equivalents of NMRA are used.

PS- David, would I be correct to assume that you are the creator of the "Edison Court" module/layout shown in photos on the group site?  Very fine work- captures the time period and the look of northern Illinois towns quite well.
« Last Edit: February 26, 2018, 12:09:48 PM by thomasjmdavis »
Tom D.

"The difference between the difficult and the impossible is that doing the impossible is usually more fun." (my college design professor Russell Whaley)

Maletrain

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Re: Platform height & wide locos
« Reply #11 on: February 26, 2018, 12:32:53 PM »
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Quote
Metra minimum tangent distance from adjacent track centerline to platform edge is 5ft 6"(0.412"...10.5mm)

That works out to only 1-3/4" less than the B&O 30" distance from the gauge line (assuming Metra is using US Standard Gauge track).  So, my thinking is that putting the platform edge up against the ties is still too tight by nearly a foot in actual 1:1.

Being based in the UK adds another wrinkle if that means that some 1:144 equipment might run through your station.  That would stick out farther than 1:160 models of the same thing.  And, that also means that you may not be able to find the "worst case" by polling members here about US equipment.

So, I think the best bet is to either use the modeling clearance standards for the UK or Europe or maybe Japan, if you can find such things, or at least the clearance standards published by the US NMRA, which should allow clearance for all U.S. prototype equipment in N scale.

narrowminded

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Re: Platform height & wide locos
« Reply #12 on: February 26, 2018, 02:12:34 PM »
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In the interest of caution after the research has been exhausted and a decision made, would it be much trouble to have a drop in piece of platform, removable for that unforseen instance when it matters?  Or maybe just a swap out platform deck, one wide and one narrow?
« Last Edit: February 26, 2018, 02:32:17 PM by narrowminded »
Mark G.

Chris333

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Re: Platform height & wide locos
« Reply #13 on: February 26, 2018, 03:54:18 PM »
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Make a mock up and run a train. If it hits it won't work  ;)

Northshorer

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Re: Platform height & wide locos
« Reply #14 on: February 26, 2018, 04:24:07 PM »
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Fortunately the likelihood of non-US stock running is very small, and yes Edison Court is my 'creation' though it would not be possible without the 3D printed models of interurban cars by  another member of our group (Boxcar Models on Shapeways).

The removable platform idea is an option I would like to avoid if at all possible. I'll take on board all the suggestions and set a demo up again to look at all the possibilities. Many thanks for all the useful advice

David