From water to air, and more forecasted snow!?

Question

while frosty cold questions are all the rage right now, heres one more to shiver over.....

probably more so in steam locomotives that diesel (and certainly even with air systems with 'air dryers') the air operated systems from brakes to bell ringers can have moisture in them. moisture as we know can freeze, and in a brake system this isnt advisable. at the same time, having your communication/warning device freeze up isnt too much fun either. simple solution ofcourse now, is alcohol. but is it used in railrway applications? coupling frozen cars in a yard surely lets in moisture from the glad hands up to the valve. as soon as those cars are coupled and valves opend to tie into trains brake line, theres your water in the line. i can well imagine this can give false brake pipe gauge readings (or fluctuating ones) and irratic brake behavior during applications. i also imagine this being worse in the age of steam, that which is of lesser technology than today. not to mention air gets warmer when passed through the compressor. that has to be a devastating combo. is there a bleed down of air from the last car (farthest from supply point thus pushing out water.) before 'pumping up the air' for a departure?

Anonymous · Accepted Answer

As stated above there are special pop off valves that remove most of the accumulated moisture in brake systems, not all. The newer ones that do tiny little pops almost continually are a lot more effective then the old ones that would make you jump 3 feet if they popped right next to you. 
Some locomotives that opreate in very cold weather have air driers also, I dont know how they work, never paid much attention. 
Cold causes more trouble with the brake systems than moisture, air hoses get stiff and gaskets harden and it is difficult (sometimes impossible) to maintain air pressure on a long train, DPU has eliminated much of this but not all trains have DPU.
Snow and ice in switch points cause as much delays as anything. 
I have been out in howling wind and drifting snow so bad that two guys with switch brooms couldnt work fast enough to clean out a switch. 
Winter can be a challenge.

Andy · Answer

Freezing weather can play hell with trains.I've never really had many problems with locomotives but the brake pipe of the train is another story.Pop off valves on the engines main reservoir tanks and the air dryers help a bunch.We have had cases where they had to put alcohol in the train line to unfreeze them.The problems start when you have to set the brakes.Cold dense air flows much slower and sometimes when you set the brakes it can take forever to get them to release.On a very long train setting the air means you have to stop sometimes instead of trying a running release.I try to leave the air alone when running in freezing weather.I was following a train recently and the engineer set the brakes several times instead of running smart and slowing down before he started downhill.Each time he did he had to stop and it took him almost an hour before we all got moving again.I have never seen them do a bleed down on the rear of a train to remove the water,but that's not to say they don't.

Samurai Hoghead · Answer

Andy is right. There are preceedures for blowing out the head end but if it gets that bad they'll use some alcohol.

The cold plays hell with the air, fo sho...

But I suggest to guys when stopped and walking around the consist, use manual drains if they are there. You'll be surprised sometimes at how much is still in the tank...

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From water to air, and more forecasted snow!?

3 Answers