Well Mike, you are correct in part.
The Emergency Brake Valve was another one of the (I believe) ex-parte orders that, for steam, mostly came out during the '40's.
This also included the firedoor order, power reverse gear order, the clear vision vision window order, to name a few. How many I'm not sure of. The Ash Pan rule came out earlier I think.
As for the triple valve on engine businss, there were no ex-parte orders to that effect as far as I know. The Steam rules covered much of that.
However, it is possible that the ICC was not "hot" to have all the smaller Grande power improved. This maybe due to a number of reasons:
1. Much of the older power had the water brake applied. This has other implications if you think about it.
2. Having active automatic air on the engine along with using the water brake - if you had no way of releasing the driving brake, flat spots could easily be the end results.
3. Additionally, use of retainers and cycle braking would have been normal operation so having to "bail" off the independent continually, would have probably not set well with some of the older heads.
4. There may not have been much concern about it because of the general operation and there were many 'old heads' around that were "tried & true".
5. Had there been a number of incidents, espoecially resulting in injury or deaths, attributed to lack of active automatic on the locomotves, the ICC would probably raised hell about it and demanded that feature be added.
6. And of course the best reason of all not to have a engine mounted triple, it costs money to install, maintain, and something else that would fail at the worst possible time!
Now the RGS 20 has (at least it did have) a cut out cock in the cab to release the driver brake pressure after an automatic reduction and that is using a standard S-3 independent brake valve.
There would have been a fair amount of air & noise in the cab of the 20 when coming down a 4% hill, cycle braking with retainers after every reduction with the air being released from the driver brake cylinders. All part of normal operation.
That additional cut out cock (sometimes referred to as a mountain valve or cock) would not be necessary if a S-3-A independent brake valve were used as that was set up with a double check attached to the S-3 body allowing the engineer to release the brake as one would with the S-6, S-8, SA-26 etc Ind. Brk. Valves in full or quick release positions after making a reduction.
If I recollect correctly, didn't the C&S engines have a engine mounted triple along with the tender triple? As the C&S did not use the water brake.
As for noise in the cab, consider that when using the automatic when cycle braking, the preliminary exhaust from the equalizing reservoir followed by the secondary exhaust from the brake pipe, none of which was vented below the cab, as is now the case, would make for a noisy environment.
Also, in the older G-6 Automatic Brake Valves, the old solid equalizing pistons would bounce on the seats during a reduction if the train was of any length.
No wonder most of those fellows were hard of hearing after years of service.
Chris
