The turntable at "work" has some rather questionable throttle levers and throttle valves on it and I was curious how other outfits have their air powered turntables set up. The set up we have leaves much to be desired especially when it comes to coaxing fine adjustments out of the motor.

The handles that are on it now are probably something cooked up by the previous management and may not be what the turntable had when it was in service.

I'm also curious what types of valves are being used for the throttle, i.e. globe valves, ball valves etc.

Photos would be greatly appreciated. Here are shots of the two handles, as well as one of the air motors.

Joe,
That Kitz Globe Valve is dandy, if you want to get a lot of air with a minimum of resistance.

A suggestion is a quick and simple throttle valve. The attached link shows
" V " notched ball valves. A 30 degree V opening opens more gradually than a 60 or 90 degree opening, thus has finer control. Caution : I would not rely on a throttle valve for positive tight shutoff. The nature of throttling will wear the seat rapidly. I would have another valve in series for tight shutoff. I would even consider a tee in the line between the shutoff and throttle with a leakoff valve on the branch. http://www.valtorc.com/valves/v-ball-valves/v-ball-valve-brass-specs

What do all those levers and linkages on the air motor do?

Funny you should ask.

1) Reverse Lever
2) Clutch Lever
3) Manual Adjustment Clutch Lever [Disconnected]
4) Clutch Lock Pin
5) Footbrake pedal
6) Air Supply Valve
7) Throttle Valve
8) Bleed Valve
9) Sand Pipe
10) Safety Chains
11) Access Ladder

Hi Joe 6167
Suggestion maybe you should contact the Conway Scenic RR, in North Conway New Hampshire. they have an air operated turntable from the Maine Central. Their turntable is 85 " long built by American-Bridge & Deck, in1926.

OK, I thought #9 was to call down, "finished with engines!".

But seriously, who cares what the air valve sensitivity is? You are supposed to drive this with the clutch and the reverser.

Steve,

The clutch is a dog clutch and it's either engaged or its not. The problem is when you try to line up the turntable and you are out of alignment by literally 1" and need to coax literally one good chuff out of the motor to get that inch. The throttle valves that we have are so wonky that you can't get that fine control, so when the motor finally does kick in, you up end being 3" off in the direction you wanted to go. Now you've got to try and back up and try again... It's a real pain in the neck!

Doesn't help that the valve with the red handle has a bad leak in it, or that the handle comes off (just because the nut that holds the valve handle to the stem came off or was never there or... who knows.

As an added bonus, you can't quite see the alignment of the rails from the operator platform and need a spotter to advise if you're lined up!

The turntable was actually built with a hand crank in addition to the air motor controls, but was removed later in its life. I bet in came in handy for getting her lined up that last inch!

Here's a photo of the clutch.

I still think the reverser, clutch, and brake are the key. Look at the controls. Those levers and pedal are the focus of action, the air valve is just a distraction. How strong is the brake?

It will stop the turntable (once you close the throttle).

But as I mentioned previously, you can't quite see the exact alignment of the turntable from the operator's platform, so when you do stop the turntable, you always end up an inch off!

And of course that means you can't engage the "skate" that slides between the rails and keeps the turntable from moving when loading or unloading equipment.

The problem is that there is too much tempered frosted glass and flower planters. All that interferes with the raw machinery and things just get wonky from there.

Why not just add the manual wheel back in? Or is that hopeless?

What does the red valve do, BTW?

Too many guts were removed for that to be possible.

The red handle (#8) is a bleed valve located between the throttle and the air motor. I figured out what it was for when "it" happened: I had the turntable PERFECTLY lined up, while I was still standing on the foot brake, and when I stepped off the foot brake, well, there was still a bit of air trapped in the motor and she let out one last feeble chuff, but that was enough to move the turntable out of position!

So yes, it is there to bleed out any air trapped between the throttle and the motor when stopped in order to avoid the previously aforementioned scenario!

More neat trivia, the air supply for the motors is connected to the rest of the turntable by gladhands so that in the event of something happening to the air system you could run the motors off the brake pipe of a locomotive (with an extension brake hose).

That's a modern mist oiler and lock out valve on the edge of the operator platform.

On the first pic of the thread, you have a picture of a red color valve with a crank handle, seperate from the rest i guess...i meant what does that handle do?

That is the throttle valve that we are thinking of replacing and trying to determine what other air powered turntables use in that role.

As you can see it falls of as it is missing the nut that should hold it all on to the valve stem. We think it is some fanciful contraption devised by the old management. I think it may have just had a plain valve handle when it was in service.

To get the nut back on we'd have to take that whole handle apart, but of course the handle continually slipping off has damaged the stem as well, which also leaks, so it may be time to replace it.

The question is, with what? Another globe valve, or does anyone have any better ideas. That is what I'm trying to find out through this thread!

Can you jockey the table using the reverser?