Clearance

[steel]

What is the min. distance from the top of the rail to the bottom of an overhead structure (Bridge, tunnel, etc.)?

[steel]

What is the min. distance from the top of the rail to the bottom of an overhead structure (Bridge, tunnel, etc.)?

[rogerhensley]

I can't answer that exactly as it depends upon which AAR car Plate you are using. The Plate diagrams show the maximum height that a rail car can be for certain clearances.

The 1948 AAR Plate B was 15' 1"
Plate E - 15' 8"
Plate F - 17'
Plate H - 20' 2"

So you can see that you would expect the structure to be higher than that. I believe that the overhead wire clearances on the NEC is about 21'.

I'm sure that someone else will have a more definitive answer than this.

[rogerhensley]

I can't answer that exactly as it depends upon which AAR car Plate you are using. The Plate diagrams show the maximum height that a rail car can be for certain clearances.

The 1948 AAR Plate B was 15' 1"
Plate E - 15' 8"
Plate F - 17'
Plate H - 20' 2"

So you can see that you would expect the structure to be higher than that. I believe that the overhead wire clearances on the NEC is about 21'.

I'm sure that someone else will have a more definitive answer than this.

[rogerhensley]

Duhh! It just dawned on me that you might want to know about clearances for your modeling. Take a look at:

Standard S-7 Clearances and the NMRA Gauge
at
http://www.nmra.org/standards/gauge.html

[rogerhensley]

Duhh! It just dawned on me that you might want to know about clearances for your modeling. Take a look at:

Standard S-7 Clearances and the NMRA Gauge
at
http://www.nmra.org/standards/gauge.html

[steel]

Thanks Roger, that is exactly what I was looking for!!

[steel]

Thanks Roger, that is exactly what I was looking for!!

[eastcoast]

hey steel,
I am experimenting with the clearances of the east coast. In my modelling , I found that real world measure of 3 to 4 inches is pushing the issue but makes a great conversation piece for viewers who doubt that the cars will clear my bridges. Hope you read my reply.
ken_ecr

[eastcoast]

hey steel,
I am experimenting with the clearances of the east coast. In my modelling , I found that real world measure of 3 to 4 inches is pushing the issue but makes a great conversation piece for viewers who doubt that the cars will clear my bridges. Hope you read my reply.
ken_ecr

[DSchmitt]

Actual Prototype clearances vary. Easten RR send to have more clearance restrictions than western RR mainly because the were constructed earlier. In the 1930's there was resistance to increasing the height of the standard box car because many eastern RR would not be able to handle taller cars on some of their lines. I read somewhere that one of the reasons for the B&O wagon top design was a taller car that could still get through the tunnels.

An interesting model operation would be to have a line with restricted clearance and a round about route to bypass the area.

[DSchmitt]

Actual Prototype clearances vary. Easten RR send to have more clearance restrictions than western RR mainly because the were constructed earlier. In the 1930's there was resistance to increasing the height of the standard box car because many eastern RR would not be able to handle taller cars on some of their lines. I read somewhere that one of the reasons for the B&O wagon top design was a taller car that could still get through the tunnels.

An interesting model operation would be to have a line with restricted clearance and a round about route to bypass the area.