Western Railroad Discussion > Hy-Rails and Other MOW Equipment ?

To our professional railroad members,

Why is it that most Hy-Rails trucks and MOW equipment don't
activate signalling and crossing circuits? I know the mechancal
reason--insulated wheels. But, from an operational point of view
wouldn't that provide additional protection beyond verbal authority
from "track and time". The question is driven by a commercial video
tape I have from a cab ride on METRA where the crew talks about a
Hy-Rail truck "getting nailed" by an train because the operator had
gotten on the wrong railroad.

Marty Harrison
MP 208.1 on the UP's Sedalia Sub

Most of the hyrail trucks that I have used were equipped with shunts so we could activate signals. We would disengage them when we did not wish to do so, usually around crossing and in interlocking plants as the shunts don't always make the best circut and can put the signals in time. This was always frustrating to the dispatcher when you tied up his territory for 10 min when you only needed a few seconds to get through his plant.

The vehicles often had dirty wheels, or weren't heavy enough to be reliably detected by the signal circuits. Therefore, the railroads simply insulate them, so everyone knows the won't activate the signals, and won't rely on signal detection for protection.

The intermittent detection also makes the signal system go crazy - chattering relays and increased communication load to pass the occupancy information to the dispatching office.

Isolation also allows the vehicles to stop within the crossing detection circuits without activating the crossing protection.

I think that there is an FRA (old ICC) signal rule that requires 7 ton axle load to be counted for signal shunting purposes. As pointed out in the above answers, these trucks are often too light, wheels are dirty, painted, rubber tread, etc. and cannot be relyed on for signal protection against trains. The optional shunts using wire brushes for crossing activation is not as critical. The Hy-Rail operator can see if the lights and gates are working, and will only proceed through a crossing if the way is clear. No signal shunt? Just wait for traffic to clear or send out a flagman, but still be governed by actual conditions that you can see.

I know if my hyrail shunted the signals all of the time, it sure would be hard for me to troubleshoot track circuit problems.

Xingman
http://home.internetcds.com/~xingman/

Thanks folks,

As the saying goes "now I know"!

Marty