Before I go down a rabbit hole, I’ll ask here. I’m looking at working on the brakes on a freight car that has two 10” cylinders side by side piped together. Valves are ABD. With this additional air volume, is there a difference in the control valves from your normal single cylinder setup?

Thanks in advance.

From my understanding if the cylinder volume is adjusted you can get the same application ratios by adjusting the volume of the auxiliary and emergency reservoirs by a similar ratio.

However, due to the need to move a larger volume of air thru the same sized orifices the reaction time is slower and some of the functions that use fixed volumes inside valves or pipe bracket will become erratic in operation.

some questions...

Is there one combined reservoir or two?

Are there any other valves like a J-1 relay under the car?

Is there a pipe connected to a 3/8" flange on the "front" of the pipe bracket? (opposite the "back" where the regular pipes are connected)

There should be no differences in the control valve. In my experience your situation is handled with the brake cylinder line going to a dummy reservoir and a J relay valve supplying air to the brake cylinders out of reservoirs that are charged through a check valve and choke. This is not an uncommon situation.

Thanks for your quick responses. I’ll be crawling under the car on Saturday to inspect the rigging, see how it’s plumbed and get the brake beams freed up.

There are no extra pipes on the bracket that I recall when I glanced at it. There very well can be a J1 and a second reservoir stashed under there, I’ll know more when I get under there. Nice to know that the valves should be run of the mill.

This is covered in David Blaine's "Modern Freight Car Air Brakes". The ABD pilots a J1, which controls air from an auxiliary reservoir to the cylinder(s).

I spent the day under the car yesterday. Here’s what we have: AB valves, nothing out of the ordinary, standard arrangement. No second reservoir or J1. Where it differs is the two 10” cylinders. They’re side by side, plumbed together with a simple tee, no check valves. The pistons are both connected to a triangular plate that connects to the cylinder lever. They work in a simple parallel fashion. The piston travel is to be maintained at four inches so overall so the air volume is roughly the same as one cylinder with full length travel. There’s a manual slack adjuster to help maintain that 4”.

So I think I may have answered my own initial question - no special porting? I’m a mechanical guy, not a pneumatic guy so hence the question. BTW, this is a 1951 vintage GATX tank car.

But now I have another. Does anyone have a “best practice” for freeing up the stuck brake beams before I go medieval on them? Simply beating on them doesn’t work. The beam slots in the side frames have wear plate that were apparently closer tolerance than usual and corrosion over the decades has locked the beams in place.

Is there a reason that repeated dousing with penetrating oil and solvent combined with heat and then judicious 'attitude adjustment' with something like a power hammer would not be helpful?

How about soaking it with panther piss for awhile, and then putting the air to it ?? I'd bleed it off and try to dig out the accumulated flake rust next, then repeat these steps as needed, unless (of course) there is some reason that won't work... I guess you could rig up a come-along or chain hoist and try persuading it to go where it doesn't want to go, too... Oh wait, I got it, after you warm it up with a rosebud, splash some cold water on the trouble spots. And since you have two brake cylinders in parallel, you might try moving them individually to start unclogging the slots.

Good luck, and be sure to give it a thorough cussing.

The slots are cleared of debris. What appears to be possibly jamming them is rust behind the wear plates and on the tongue that rides in the slots. It’s like they’re welded in place. I think my next approach will be to keep everything soaked with Seafoam for an hour, hook a come along up to provide tension and smack the crap out of them some more. If that fails, then I’ll drag the torch out. With my luck, I’ll run out of gas. My arms are gonna tired….

Dunno about Seafoam, but I bet turpentine will thaw it out cheaper. Hook up the come along, tighten it up, pour in a bunch of turpentine, and leave it sit til Monday. (If possible, get somebody to soak it a few times over the weekend. Hammer while pouring.) You could also try to wiggle the brake beam by hammering a chisel into one side of the slot, then remove it and do the other. Once you get a little, tiny bit of movement, the rust will start to break up and begin to crumble and drop out of harm's way, UNLESS it piles up where you might have to blast it with a blow gun or suck it out with a shop vac. In that case, beat on it with a hammer at the same time.

PS ---Turpentine is a great rust buster, but it has no lubricating qualities. I like KROIL, but it's not cheap...

I’m a fan of Seafoam Deep Creep. It seems to penetrate a little better than Kroil. In my experience, heating a stuck nut is the only thing better than Seafoam. But that’s me. I’m sure everybody has their favorites.

Doesn't have to be 'either-or' with the penetrant: You want something with solvent that gets readily into the 'nooks and crannies' of the rust, with detergent to aid in dissolving the oxide structure, and you ALSO want an oil that keeps the solvents etc. from evaporating quickly before they penetrate. Ideally there would be solvents and heavy oils (not the fish or light oils in the 'water displacer' types of product) but the result might be to apply a coat of nonevaporating oil over the 'area of work' each time you spray in a fresh load of solvent. Or wrap the joint with Saran or some other barrier that keeps the light stuff from evaporating too fast. You might even build a little dam or poultice or whatever around the parts, and keep the inside saturated...

I am a fan of heating and then quenching with spray. This can produce some nifty flash but you'll quickly get down below flashpoint -- wear PPE and use care accordingly. You want to use the thermal expansion and contraction with active wet solvent present, to the greatest degree possible.

In my opinion 'beating on the joint' greater than vibrating solvent into it is counterproductive until the joint is fully saturated. You should be encouraging capillary action until then... think of it as the chemical equivalent of 'let the tool do the work'. (This is also why I advocate a reciprocating air hammer rather than a sledge.)

I'm thinking along the same lines. After the Seafoam penetrates in and has it wet, I'm thinking of spraying it with some ancient fuel oil/kero we somehow inherited. It's so old it doesn't hardly burn but it's has a bit of a slick property to it and won't gas off quickly. Heat is also potentially in the mix.

As for the air hammer, if we had one big enough, like a clay digger or hot rivet hammer with a flat hammer bit, and I could maneuver it around under there, I'd use it. I'm on the ground under the trucks and there really isn't oodles of room to work in. I might try knocking it with a 12# sledge using the mass to my advantage instead of a 4# maul while I have a come along under tension. I've gotten it pretty well cleaned out and once I get it to start moving, I can flush any resultant muck and crusties out as I go and then work some of the rust out from behind the wear plates. I gotta say that everything isn't rusted so bad that you'd look at and say "that'll never move", they're actually not that bad at all. Just stuck.

I'm all about working smarter, not harder. However the lack of a fully equipped car shop kinda forces you towards harder.

In my experience, beating on a stuck RR car part with a hammer is not usually effective and all it does is damage or break the part you're hammering.

I have much more luck with the slow, steady and powerful hydraulic muscle of a bottle jack or Port-a-Power. Figure out a way to get a 10 or 20 ton bottle jack into position to break loose the brake beam. You may have to place the jack sideways/horizontally, and find something to push against. You have to be creative and maybe even weld up a fixture of some kind for this to work. This is just a thought. But usually a lot of heat from an oxy acetylene torch will do wonders with loosening rust and rusty parts. Also, could you remove some of the brake hanger pins to help break things loose?

Yeah, I’ll be dragging out the torch and a bottle jack along with everything else. I am going to try to soak it and knock them loose with tension on them first or with the jack if I can get it in a good position.

There’s almost no slop in the rigging since it runs on only a 4” cylinder throw. Hence everything on the trucks is disconnected or I’d be fighting that, too.