Tunnel Specs

[Anonymous]

Does anyone know the AAR standard for height of tunnels, top of rail to crown of tunnel? And did that figure change from a lesser number before the advent of Hi-Cube cars? If so, about when did railroads implement that greater height? I'm going to be modeling D&RGW (standard guage)in the mid-1960's, and I don't know whether tunnels had already been heightened by that time, or later on. Thanks in advance!

[Modelcar]

Looked in Civil Engineering Data: Railway Engineering.....TM 5-628 / AFR 91-44
It states...22' from top of rail to overhead obstruction...Sorry, didn't see a date.

QM

[Anonymous]

If you are modling the D&RGW I prsume tha it is the moffat tunnel route you are interested in. I recall Reading the Denver Post that the moffat Tunnel can not handle double stacks. This limits what the hight of the tunnels on that route could be.

[mudchicken]

AREMA Standard 1-8.3.1 (1994) states 9'-0" wide from centerline, 23'-0" above top of rail, 12'-0" radius on top with spring line at 17'-9"5/8 above top of rail. Dimensions changed in 1935,1950,1966,1970,1994 with last changes to allow for doublestack containers....AAR does not dictate tunnel specs. It does dictate freight car clearance envelopes. Tennessee Pass, Moffat, Pando et. al. have not changed recently. Advent of the High-Cube cars was in the early 1950's...

Consult a college engineering library to get copies of older AREA/AREMA manuals....