I’m modelling an HO station and need to know the following:
A. the modelled distance
or
B.the prototypical distance
from the platform edge to
C.the nearest rail
or
D. the nearest tie end.
For a standard low platform on tangent (straight) track, approximately 5’ to 5’-2" from track centerline. Hope this helps.
According to the “Baltimore and Ohio Railroad Standard Plans for Maintenance of Way and Construction”, dated December 1907, the edge of a low platform should be 2’-6" from the inside of the nearest rail, or 4’-10 1/4" from track centerline. The edge should also be 4" higher than the top of the rail and slope up to the station building at a rate of 1/4" per foot. The station building should be a minimum of 16’-0" from the edge of platform.
More info.
The modern AAR standard low platform is 8" above top of rail (TOR) and 5’ to 5’-2" off centerline in order to clear the trucks and side sills of a plate F car (including an Amtrak Superliner, gallery car, or commute bilevel). These measurements can vary by location (for example, technically such a national standard platform violates the archaic Texas Clearance Law, although we and others have worked around that on occasion), but typically the initial (as constructed) paved platform height can run from TOR up to 8-9" TOR, or less if it is an older platform and numerous track lifts have been done. I have seen platforms below top of tie, particularly on lines that downgraded their passenger service early and earnestly (SP is a good example). Many platforms, particularly at multi-track stations, were originally designed and constructed at TOR to facilitate installation of service and passenger crossings without reconstruction of the platform to provide ramps (an issue with the modern 8" TOR platform). Additionally, some of these platforms also included paved surfaces between the rails, thus requiring a platform height at TOR.
Gravel and dirt platforms are typically at top of tie or a little below, up to edge of the the ballast crib.
Since the 1980’s, a new modern platform also requires a 2’ wide tactile surface along the track edge(s) for the length of the platform, in a contrasting color, in order to meet the Americans with Disabilities Act (ADA). Retrofits to existing platforms in use are also generally required for some systems.
Prior to that time, a 3-4" yellow or white line was painted on the platform approximately 2’ from the edge as a safety warning.
You should check data for your prototype (assuming you are modeling one) as to station setback and platform height and clearance, as the numbers can and do vary. And remember, depending on era, what was actually on the ground may vary considerably from as-built.
For raised platforms, what is the actual dimension?
I generally just place the appropriate car and scale from that. But would like to know the real world numbers.
Bob K.
I can’t speak of prototype dimensions, or of exact model dimensions (which, obviously, vary by scale,) but I can say that the NMRA Standards Gauge includes a notch for high platform clearance that agrees with the AREA standards for platform height and clearance as of 1940.
In my own modeling, I’ve had to compromise by allowing clearance for over-scale-width steam running gear, which was determined by eyeball and (oops!) never written down. Since I model in a scale not “standardized” by the NMRA, the actual dimensions would be only marginally helpful.
Chuck.
Standards or no standards, make sure your rolling stock clears the platforms before you glue anything down, and before you paint the edges if you’re scratch-building. Be particularly aware of overhangs if you’re putting the platform within a car-length of a curve, too.
I am a high platform man and agree with the approach of Chuck and Mister B. Measure the locos and the passenger cars and place the platform as close as possible without fouling those. It has to be as close as possible to avoid an unsightly gap. Watch out for swing of long cars if the approaches to the platform have any curve, and better check your freight cars for clearance if they will be running through.
Keep the gap to a minimum. Don’t want the little plastic fellows falling down between train and platform.