Nostalgia & History > What was "brake shoe smoke", anyway?

We've all seen pics of trains descending grades in a cloud of "brake shoe smoke"-- even decades ago, before composition shoes, when the brake shoes were ... just cast iron? Or something else added?

It finally occurred to me to wonder: if the brake shoes were just iron ... is the iron itself burning? And the smoke is minute particles of ferric oxide or some such thing? How hot does iron have to be to burn? If you could see the surface of the shoe, would it be white-hot?

If a train with modern-day brake shoes had to be braked as heavily as a pre-dynamic-brake train, would it smoke more or less than an iron-shoe train?

Most of the time it was oil & grease on the shoes & wheels heating up & smoking. Most of those older cars had plain bearing trucks instead of roller bearings. The journal box oil was thick, almost like 90 wt, and it would usually leak past the seal at the back of the box. When it did (either from a worn out/missing seal or from over filling) it ran down the plate of the wheel & onto the brake shoe & surrounding parts. When the brakes were set, the shoe would heat up first, then after a while the whole wheel would get hot, and the accumulated grease & oil would start to cook off. Roller bearing cars are a lot cleaner, and almost no grease or oil ever gets on the brakes or wheels anymore. Comp shoes will start to smoke if they get hot enough, but by that time the wheel is almost red hot too. In the daytime, about all you can see is heat waves, faint blue smoke & the horrible smell.

Most of the smoke was the built up dirt and oil residue from the bearing boxes that tends to get on the wheels of a plain bearing car.

Would some of the smoke come from grease on the wheels from flange lubricators?

Heres a little brake shoe smoke on a westbound arriving at Dunsmuir in 1961.
Robert Morris Photography
http://www.snowcrest.net/photobob/index1.html

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That's what you wanted to see coming down Cuesta with the beets. The oil from the old brass journals that coated the wheels and shoes would get hot and smoke.

When they had the old cast iron wheels, when they got hot, they would crack in a heartbeat. That's why the brakeman carried tooth pics, so they could put one in the crack so the carman could find the crack later on. Because when the wheel cooled the crack would disappear.

Passenger trains would smoke too until they got disc brakes. On most grades rules called for so many retainers be turned up on passenger no matter what.


Nudge

It wasn't much fun riding in a helper behind the train in a cloud of "brake shoe smoke" with a chain smoking engineer or fireman. Remember Nudge? You know who I am talking about...

Last time I saw smoking wheels was the final USGX (former SP) gon beet season out of Klamath. I deliberately went a little heavy on the air to put on a show for a friend in Mt Shasta. I wish Photobob had caught the night time scene at Mp 329 with a full cloud of smoke lite by the full moon over the Mountains to the east.

The good old days!!!

sphogger

sphogger Wrote:
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> Last time I saw smoking wheels was the final USGX
> (former SP) gon beet season out of Klamath. I
> deliberately went a little heavy on the air to put
> on a show for a friend in Mt Shasta. I wish
> Photobob had caught the night time scene at Mp 329
> with a full cloud of smoke lite by the full moon
> over the Mountains to the east.
>
> The good old days!!!
>
> sphogger

The the old buzzard missed that one, but got these guys:

http://www.trainorders.com/discussion/read.php?11,1127905,1127905#1127905

A Rio Grande brakeman once said "some railroad crews worry about brake smoke; up here (in the mountains) we worry when we don't see any".

More brake shoe smoke from brakes not released on the car ahead of the caboose. Stopped shortly after this photo was taken to release the brakes on that car. They had just left the Eugene yard too, about two miles or so back.

C.C.Chas.

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"Modern day" brake shoe smoke is caused by the composition brake shoes. They have a rather high amount of urea in them, which is why they also smell like a cow pissed on a hot radiator.

Right on Nudge...I've seen more than one beet train come down Waldorf with a journal box on fire too!