63rd Street Tunnel Clearance

What is the clearance in the 63rs Street Tunnel to GCM? I recall hearing that an M-8 car will not fit through it, as they would be too tall at 14'3". I have not been able to find dimensions for an M-9, but the M-7 I have found different dimensions ranging from 12'11" to 13'3".

If that's all correct (which I'm a bit skeptical as I keep finding different numbers), that would put the clearance in 63rd Street Tunnel somewhere between 12'11" and 14'2".

Is the 63rd Street Tunnel the tightest clearance on the North American FRA Heavy Rail system proper (not counting industrial trackage inside of a steel plant, coal loader, etc)?

ElectricTraction wrote: ↑Sat Nov 02, 2024 7:51 pm Is the 63rd Street Tunnel the tightest clearance on the North American FRA Heavy Rail system proper (not counting industrial trackage inside of a steel plant, coal loader, etc)?

That honor would probably the Hudson Tubes on PATH (still ICC/FRA), with 51' cars and a loading gauge similar to IRT and definitely smaller than the Dual Contract lines. Closest would be IRT contract one and the Steinway Tunnel.

The 63rd Street Line (lower level) was designed in the late 1960s for M-1s as part of the MTA's 1967 plan and was built to handle nothing larger than a M-1. The M-1s never ran in the tunnel which was designed and built for them. Single level coaches such as Comets would not fit either.

R36 Combine Coach wrote: ↑Sat Nov 02, 2024 8:20 pmThat honor would probably the Hudson Tubes on PATH (still ICC/FRA), with 51' cars and a loading gauge similar to IRT and definitely smaller than the Dual Contract lines. Closest would be IRT contract one and the Steinway Tunnel.

I'm not counting PATH, as while it is technically under FRA jurisdiction, it's operating under a waiver, and not part of the national rail network. Although there's no reason for anything other than an M-7 or M-9 to go to GCM, the trains do interoperate on other parts of their route with everything up to Plate F freight run by NY&A in interchange service.

The 63rd Street Line (lower level) was designed in the late 1960s for M-1s as part of the MTA's 1967 plan and was built to handle nothing larger than a M-1. The M-1s never ran in the tunnel which was designed and built for them. Single level coaches such as Comets would not fit either.

So the M-1 is 13' plus horn, so maybe 13'3" seems pretty close? Does anyone know what the actual clearance is? I can't think of anywhere else on the national rail system (excluding PATH) with a tighter clearance. That makes even the North River Tunnels at 14'6" with clipped corners seem like hulking giants, even though those NJT MLs look like toys running on the NJT Raritan Line next to 20'02" ATR Plate H doublestacks.

Per the LIRR equipment data book (1977 edition, page 23-24), M-1s have a 12'-10" height.

R36 Combine Coach wrote: ↑Sun Nov 03, 2024 12:30 am Per the LIRR equipment data book (1977 edition, page 23-24), M-1s have a 12'-10" height.

If you believe Railroad Wiki, the Comet cars are 12'8". Do they really not fit, or are there just no locomotives that small to move them through the tunnel? Or is it like the East River/North River situation where the shape of the corners starts to matter?

If you believe the smallest dimension of the M-7 cars at 12'11", it's certainly plausible that the shape of the 63rd Street Tunnel will allow an M-7 at 12'11" through, but a Comet car at 12'8" is an inch or two too squarish to fit. The Comet cars are pretty much a box, while the M-7 has an arched roof (specifically for the 63rd Street Tunnel clearance?).

https://en.wikipedia.org/wiki/Comet_V#/ ... Comets.jpg
https://upload.wikimedia.org/wikipedia/ ... 2023_M.jpg