Steam & Excursion > Sierra Railway & straight air brake question

The Sierra equipped at least a few of their engines with both an automatic air brake system and a straight air system for use in places like the Don Pedro Branch where there were 5 percent grades. My question is, were there rules or laws in place regarding the placement (on the Sierra or otherwise) of each brake pipe (i.e. inside vs. outside) and were there differences in pipe and/or glad hand size to distinguish one from the other?

FWIW Reading Company had an electromagnetic brake on the Budd built Crusader, the FP-7’s had a special connector on their nose for the cable.

I don't think there are/were any specific AAR or ICC rules covering the straight air brake, because it was not used in interchange, and such rules were all about interchange traffic.

However, WABCO always *recommended* positioning the straight air pipe ("SAP") on the opposite side of the coupler to the trainline, and angling the hose as a mirror-image of the trainline (that is, at 30 degrees from the vertical, 60 degrees from the horizontal). Also, the SAP was usually only 3/4" IPS, much smaller than the trainline's 1-1/4" IPS. The gladhands used on the SAP are usually H-type, which will not couple with the F-type used on the trainline. The SAP was not widely used in the US (in fact, I didn't know that the Sierra used it), but it was common on many of the heavily-graded railroads of western South America (Central and Southern Railways of Peru, Arica-La Paz, Antofagasta-Bolivia, Cerro de Pasco, Southern Peru Copper, Orinoco Mining Corp., etc.). In fact, we at WABCO were kind of tickled that, in the 1970's, some U.S. Steel Corp. railroad staff came back to the U.S., after spending time on the Orinoco Mining line in Venezuela, to introduce this "great new feature" they called the "Orinoco Retainer" to the ore cars of the Duluth, Missabe & Iron Range (both RRs at the time owned by USS) -- not realizing that (a) the SAP had been first used on the Denver & Rio Grande in the 1870's, (b) WABCO had re-designed the system specifically for Orinoco Mining when they first built their line in the late 1940's, and (c) WABCO had suggested it many times previously to the DM&IR, but they had not wanted to implement it (maybe there was a bit of "NIH [not invented here] factor") at work there!

Roger Lewis (airbrakegeezer)

Roger,
Thanks for the info. I found out the the West Side Lumber company used straight air also and that they had the hose opposite of the automatic air so that the hoses crossed in an "X" when laced up. But on the front of the Sierra locos, both hoses are on the engineer's side.

How does it work? Direct air to brake cylinders just like Mr. Westinghouse's original air brake? Or something else which that "Orinoco Retainer" term sort of implies?

There was a filling piece with a double check valve which bolted on between the triple valve and whatever it bolted onto (brake cylinder or pipe flange when not bolted directly to the BC). The double check valve sorted out whether the air in the brake cylinder came from the straight air pipe or the triple valve, just like it did with the SWA locomotive brake equipment, although the DCV was mounted by itself in the piping, not in a filling piece.

The Durango & Silverton has an interesting auto / straight air brake system as well, which only works with K's. There are two brake pipes that run the train, one for auto and one for straight. When you want to run with the auto / straight combo, you have to cut out the line to the retainers, and when the straight air is applied, it sends air directly into the brake piston exhaust. This way you can use both auto and straight without any difficulty. However, if you want to use retainers, you can only do so by cutting out the straight air, and cutting the retainers back in.

>This way you can use both auto and straight without any difficulty.

You can do the same with the filling piece installed, which is exactly why it's there. The only operation I know of which used these was Westside Lumber and perhaps Pickering, and there are pieces of this brake system still around. This isn't to say there weren't other operations which used the system, but I never heard before of the Sierra using it.

EtoinShrdlu Wrote:
-------------------------------------------------------
> >This way you can use both auto and straight
> without any difficulty.
>
> You can do the same with the filling piece
> installed, which is exactly why it's there. The
> only operation I know of which used these was
> Westside Lumber and perhaps Pickering, and there
> are pieces of this brake system still around. This
> isn't to say there weren't other operations which
> used the system, but I never heard before of the
> Sierra using it.

Yes, Pickering did in fact use the straight air system.

Brian