Re: Retainer valves

Tim O'Connor


The retainer line is a small diameter pipe from the AB valve with the
retainer on its end. Retainers can be mounted anywhere, but they need to
be easily accessible to train crews - and maybe they were mounted high up
on cars for security or safety reasons, I don't know.

But when low mounted brake wheels were introduced, new cars were built with
the retainers directly accessible under the sill (on box cars). I've also
seen retainers mounted low in the end cages of hopper cars.

Side mounted retainers are on only one side of the car. In the old days a
brakeman would walk the line of box cars (for example) and set the retainers
on a specific number of cars - according to whatever rules were in force, and
he carried a rod so he could reach up from the ground and set the retainer
(which has several positions) - and reset the retainer later, the same way.

Retainers became much less important with the introduction of dynamic brakes
but they're still needed in many places.

The old Cal-Scale (now Bowser) AB brake set included this diagram. There are
lots of other diagrams and images online.


Isn't the retainer located near where the triple valve located?

still a student,

Gary McMills

Tim O'Connor
Sterling, Massachusetts

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