[PRCo] Re: Pittsburgh 1200s

[Boris Cefer]

Yes, the photo came from me.

As I understand this design, there was one lever (pull rod) on each truck.
The small air tank was only an auxiliary tank. When the cylinder was under
full pressure (tread shoes released), the check valve (the bottom one)
allowed the pressure to fill the auxiliary tank. When it was necessary to
release the brakes in an emergency (no pressure in brake cylinder and
connecting pipes), pulling the rod opened the upper valve which allowed the
pressure to enter the brake cylinder and release tread shoes. Of course, the
valves had to be perfectly tight to keep sufficient pressure in the small
tank for a sufficient period of time.

B

----- Original Message -----
From: "Holland Electric Rwy. Op. H.E.R.O. -- Import SPTC 1.48 Models //
James B. Holland"


> I believe that Boris provided us with this photo of the 1200 truck and
> brake system:::::::
>
>
> http://lists.dementia.org/files/pittsburgh-railways/1200s%20brake.jpg
>
>
> Assume that lever near the bottom right which runs toward the cylinder
> near the upper left is the one that is pulled to release the brake
> ----    also assume that this must be done on each axle.