Air Brake Condensate

NW Mailing List nw-mailing-list at
Mon Dec 28 23:35:58 EST 2020


Thank you for the information.  I just never gave the air brake system a
thought about winter time conditions causing problems until my friend
Dennis asked me about it.

Sam Holben
Virginian Rail Fan

On Mon, Dec 28, 2020 at 5:31 PM NW Mailing List <nw-mailing-list at>

> On 12/28/2020 8:30 AM, NW Mailing List wrote:
> > A friend of mine asked me in the winter how did the railroads keep air
> > brake condensation from freezing the triple valves especially during
> > the steam era.  I did not have an answer nor did I ever think about
> > it.  Is/was this a problem?
> >
> > Sam Holben
> > Virginian Rail Fan
> >
> Sam,
>      The big problem was not the triple valve, it was the vent valve.
> The vent valve you might recognize as a round dish-like piece. Anytime
> the air was down close to freezing and the train went into emergency, as
> in cutting off from the train to do work, the air vented through that
> valve. The sudden drop in air pressure also dropped the air temperature
> and the thing would freeze open. When it did, you couldn't get any air
> past that car to the rear to pump the brakes off. Sometimes, they would
> reset themselves after blowing for some time. I have also had some luck
> making a normal brake application down to zero and got them to reset. If
> not, someone would have to walk the train and beat on it to get it to
> reset.
> Jimmy Lisle
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