Stopping things

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Stopping things

Post by DaveLathrop57 on Sun May 12, 2013 1:55 pm

110 was equipped with the Westinghouse 6ET brake system. 17 is also so equipped, and the centercab diesels we run have K14, which is 6ET on one stand instead of 2. So, our guys know 6ET and we're already set up for it, no reason to consider anything else. All of the brake system apart from the "pig" that holds the distributing valve were removed long ago. I have obtained a donation of the rest of the system. We are assuming for the moment that the sir reservoirs are sound. The air was provided by a single stage Westinghouse air compressor. We have the main casting with no inner components left on 110. We also have no governor or lubrication appliances for the air compressor. This opens the door to new solutions or to simple replacement in kind. What are our options?

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Re: Stopping things

Post by Overmod on Sun May 19, 2013 12:04 am

Electric rotary air compressor is the logical 'stand-in' for operation until you can get a Westinghouse compressor or the pieces to fit it. My guess is that some requests over on RyPN would produce sources for 'used' compressors and parts that might be made available at an attractive price to get an engine running.

Point taken on 6ET ... but I would still figure out how and where to insert the Rotair valve for the PTC compatibility control. Even if its location is just a couple of plugged tees in the brake piping...


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Re: Stopping things

Post by DaveLathrop57 on Sun May 19, 2013 11:13 am

I have no clue how to plumb in for PTC, would appreciate advice on where to locate the plugs for potential future installation.

Let's think about pins and bushings and places where rods rub along the tops of brake beams a bit.

Dave

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Re: Stopping things

Post by Overmod on Sun May 19, 2013 1:39 pm

The system I designed in the '80s, which is functionally superior to (and compatible with) the current flavor of PTC, uses a modulating valve in parallel with the physical brake valve. To 'plumb' for it, you only need a separate connection from the brakepipe; I think regs require separate exhaust to insure against common-mode failure.

The proportional rotair valve can be used as a primary brake valve if desired. I'd use a completely separate valve for the independent (the system was originally intended for diesels and electrics which do not have an air independent-brake system) and NOT program it in step with the main PTC-valve modulation.

I am strongly against automatic control of the throttle. The PTC system on big steam is designed to center the reverser through the equivalent of a dashpot when a penalty brake event occurs: it does NOT just 'chop power so the brakes will stop the train faster'. The situation gets more complicated in the absence of a power reverse (or a place to put one!) and I would fall back on the old excuse of an alarm or voice that gets the crew to close the throttle and/or center the reverse STAT, and won't take no for an answer and just shut up...

Pins and bushings -- hardened. Auto slack adjusters, from freight practice? I'd think so. My first instinct about rub locations is to provide an antiwear or elastomer plate, with lateral 'guides', where the rod might touch -- this could be the material used for lathe bedways,l or Nylatron like diesel pedestal liners. (NOT hubliners, but that's another story...)


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