Allen axle pump

[Postwarbob]

Our club (GGLS) recently aquired our first of 2 RGS20's for our public train. It has a RR Warehouse double ram axle pump. It supplies the boiler with all the water it needs. As a back up there are 2 Superscale Chicago Style injectors and a RV water pump for emergency. My friend and I used the same pump in our Hudson rebuild and it kept that boiler happy also. MAKE SURE YOU USE A SCREENED WATER SUPPLY !!!!!! ( ON BOTH INJECTORS AND PUMPS ) Bob.....

[Bill Shields]

you can NEVER have too many ways to put water in a boiler....

4 sounds just about right...

[Pontiacguy1]

I personally feel like a hand pump in 1 1/2" scale or larger is a waste of time and effort, but I do know some people that like them and use them regularly. It is also a convenient way to do your annual hydro test. I like the idea of an electric pump as a backup pump, although hiding the battery could present a problem for some setups.

I actually think that a properly designed and installed axle pump is the most reliable method for putting water into the boiler while moving. I have only ever had a couple of problems with either an axle pump or a crosshead pump, and one of those times was when trash got into the exit check ball and jammed it up, causing a hydraulic ram that locked up the locomotive temporarily. Once I got it unjammed, I put some in-line screens on there and have never had that problem again.

Of course, I also have at least two methods of putting water into any locomotive boiler, at least one of which can be done without the locomotive moving. The superscale injectors are really first-rate, as long as you keep the trash out of them. That little floating cup also likes to get stuck sometimes. I make it a point to take that thing out after the locomotive has sat up for a while and make sure it will slide up and down freely. I also make sure that the holes and the cones are all free of scale and trash. If they are, then it picks up great and works near-flawlessly.

Like Bill said: the more ways you have the less likely you will ever be without water. Also, if you have 3 or 4 methods for putting water into the boiler that work, then having a malfunction on one of them won't mess up your day. You can run on the other three and then fix the offending item later if you want.

[jdorn]

Bob,

Can you post any details of how and where the axle pump was installed on the RGS 20? I am in the process of building one now and have been trying to determine the best location for the axle pump. Any details or pictures would be greatly appreciated.

Thanks,
Jesse

[NP317]

Not an RGS 20, but my 90-ton Mikado:
I built a single-ram pump based on the internal dimensions of the Allen axle pump. Pump/cylinder size ratio works out similar to my Ten Wheeler.
Made a custom mount to fit it between the frames. Pics attached. (it looks like the Assembled picture may be inverted for some viewers. Sorry. You know what to do.)
The pump is mounted to the frame between axles #1 and #2, angled down and facing aft to the main driver axle #3. The pump ram rides over the #2 axle, allowing clearance for vertical axle movement.

I plumbed the tender water intake to the pump to come both from the right-side tender water shut-off valve, and through the two check valves of the tender hand pump. Two reasons:
1) When I forget to open the tender water valve (yea, that happens...) the axle pump still gets water through the hand pump.
2) Before EVERY steaming day, I close the tender water valve and use the hand pump to prime the axle pump system, while testing that the hand pump will put water into the boiler. Then I open the water valve for normal operation (when I remember...)
I have NEVER had a problem with the Allen Ten Wheeler axle pump in 13 years. It has worked properly every steaming day.
I have plumbed the Mikado water pump system the same way.

Hope this helps.
~RN

[ccvstmr]

...I would add, be mindful of the materials used for the axle pump body. Why? You wouldn't believe the pounding the pump body valve seats take. Every time the drivers go around one time...the check balls get pounded against the valve seats. Most steamers use stainless steel check balls. There are also some "softer" flouroelastomer check balls that might fit this application as well.

If you run the numbers...an 8" diameter driver makes one full revolution every 2 feet. Therefore, in a mile, those check balls are cycling some 2600+ times. If you run your loco 100 miles per year...that's close to a 250,000 cycles. The check balls might not travel much inside the pump body, but over that kind of time...the wear and tear adds up.

On my 10 wheeler pump, I replaced the valve faces with silicon bronze wafers and modified the water passages to provide enough open space for water to pass while still providing a large enough surface area for the ball to hit.

[NP317]

Bob,

Can you post any details of how and where the axle pump was installed on the RGS 20? I am in the process of building one now and have been trying to determine the best location for the axle pump. Any details or pictures would be greatly appreciated.

Thanks,
Jesse

I have a new unused RR Warehouse double ram axle pump to sell, if anyone needs it. No eccentrics or drive system.
Make me an offer.
I thought I would use it, but...no.
~RN