Allen mogul equalized pilot truck

[Raymbo]

A friend bought an Allen Mogul a couple of months ago and we brought it to our track. We found immediately that there were several issues with this engine that the seller conveniently neglected to tell us about, it was badly out of time on the Stephenson valve gear, and that pony truck proved to be a most frustrating problem to solve, but I think we have it now.

I added 4-1/2 pounds of steel flat bar to the aluminum truck and it was better, but kept derailing at some of the spring switches. A common experience with this aluminum frame thing. See photos

Today, I installed a new compression spring in the spring device under the pilot. I used a Century Spring Company C-792 7/8" X 3" X .105" with about twice the compression of that which came on the engine. I think we finally got it.....today I ran it about 1-1/2 miles around our modest track and not even a hint of a derailment. I am very pleased with the operation now.

I also found that the wheel would contact the frame on some vertical curves on our railroad so I ground a radius out of the bottom of the aluminum casting. That ended all the problems of the wheel hitting the frame. See photo

We are fortunate to have a steam traction engine aficionado who has had a lot of experience timing up a slide valve type of engine and he has worked on this thing for about 24 hours total. Right now it is fairly square, but a little more work is needed to get it to run well with the Johnson bar up close to center instead of in the corner. That will be a winter project.
https://www.youtube.com/watch?v=NZkGuhmXOnQ



The engine is a tad slippery and I did manage to add about 5 pounds of lead in the sand dome. I don't know if it helped or not but we pretend it did.

Right now the little engine is a pleasure to run and learning to fire it has helped. We can run it with the Johnson bar notched up one and the axle driven water pump keeps up with the steam use. Firing is a full time job with this engine but as we gain experience I have to believe we will get better at it.

[blff cty lcmtv wrks]

maggi;
should you go the alternative mogul lead truck route, you might want to do these changes to the lead truck frame works.
1. make your lead truck side frame pieces out of half inch thick crs flat stock instead of 3/8" stock. reason; the cylinder bars are made out of half inch bar stock. don't see any reason to change. besides, it's a lot easier put the tapped hole into the center of half inch stuff rather than trying to drill and tap a hole off to one side.

2. you will now use the 7 1/4 inch numbers for making all the cross piece frame parts. reason. this will keep everything to the overall width. you need to make the cross pieces narrower so that the overall width stays the same. i think i just said the same thing twice in a different way.

i think that is all you need to know to pull of this project.

respectfully submited

big c
bluff city locomotive works

[blff cty lcmtv wrks]

maggi;

i just noticed that you build in 7.25" gauge. you will have to alter your cross pieces even more so that they work with the thicker side pieces. you need to lose 1/4" overall in the width of your cross pieces. i build in 7 1/2' gauge down here. sorry bout that. i think i got it right.

big c

[johnpenn74]

I would only build a mogul with a proper equalized truck. Remember if its not equalized, then it is basically just a decoration.

Issue #1 - 0-6-0 suspension does not equal 2-6-0 suspension. Remember when you equalize the lead truck to the engine, you must set the springs up as 2-2-0 + 0-4-0. I have seen a few Allen Moguls that are equalized as an 0-6-0 and then a lead truck added. This doesn't work as the suspension will equalize the drivers weather you have you lead in place or not. In short, if you build a 2-6-0 and remove your lead truck, the engine had better be pitching forward, If it doesn't then you aren't equalizing the load and can expect issues from the LT truck stability. Adding piles of lead is a real sloppy solution. If you are doing this to keep the lead on the track then it indicates that either the springs are not correct the for the wheel axle loading or something is not moving and allowing the system to equalize correctly.

Issue #2 LT swing position is not back far enough. Another design issue I see is lead truck swing point is not far enough back. If you look at a few prototypes of moguls and consolidations most have the swing point somewhere Between the cylinders and the first driver axle. See picture.

Setup? I really don't understand all these references to "setting / adjusting" the lead truck. The load on your LT axle and fist driver are determined by the ratio of length on the LT equalize bar (remember out first axle is isolated from driver 2 and 3.) Unless you move the boiler center of mass forward somehow there isn't much you can do to change the load on LT axle +driver 1 combination.

Remember the LT fulcrum under the saddle usually has three pins so you can move some of the weight from the LT axle to the Driver # 1. But what ever the aggregate load of the two axles is fixed. It is my suspicision that the models suspension was originally setup as 0-6-0 because that made getting the load over the drivers to equalize out. Unfortunalley that created all kinds or issues with the lead truck.

I'll thank some of you in advance not to tell me British engines don't have equalized lead trucks.... Yes that true,... the difference is that don't have ANY equalization in the frame/ driver suspension. So the LT will get it's % of the load and lack of equalization means the drivers are not trying to balance the load of the engine.

I have been to Lucern, Switzerland and seen the 2-10-0 from the pit. Basically it is a friction plate arrangement. Springs on the side to align the truck to the center, and one pushing down to carry the load. I am sure that's what's being attempted here. It just doesn't work with Equalized drivers.

JP

[Boiler Builder]

Right now it is fairly square, but a little more work is needed to get it to run well with the Johnson bar up close to center instead of in the corner.

I spent a few days trying to square up an Allen ten-wheeler when notched up. Mr. Allen for simplicities sake did not offset the link support pin required for short cut-off operation.

[Raymbo]

Right now it is fairly square, but a little more work is needed to get it to run well with the Johnson bar up close to center instead of in the corner.

I spent a few days trying to square up an Allen ten-wheeler when notched up. Mr. Allen for simplicities sake did not offset the link support pin required for short cut-off operation.

Thank you for the response. We have been under that engine a number of times to try to get the eccentrics lined up. I was hoping we could get it a little closer than we have it now. I have listened to several on You Tube and you are right, they can be made close, maybe not perfect. Notching up may not be possible.

How I wish this engine had been equipped with Walschaerts gear instead.

Again, I appreciate the response.

[Steve Alley]

Hi Steve Alley Here
I have been reading this thread and like to comment to it. Since I have taken over this Allen Models and have try to make improvements. I saw one thing that stuck out with the casting that I received witch are aluminum. Steam Locomotive did not use much if any aluminum parts on them at all. So I switch to make them out of Cast Iron for the weight. This came about when I pick up the castings from Marty and see that the new 0-4-0 was light in the front end of the locomotive. The front axle weight was a lot lighter and would need 40 lbs in the front to off set the axles. Now we are offering the following casting in cast Iron-- Pilot, smoke box top and bottom, smoke box cover, sand dome top and bottoms, steam dome tops and bottoms, Cross head yoke upper and lowers, and Smoke stack. So with just these changes I have added 35 to 40 lbs mostly to the front of engine, This before machining of parts.

Now as far as the equalize front truck issue, We at Allen Models have 4 print to deal with this issue, but as always it works if built properly. I have taken the drawing of the front truck and equalizer to be draw in CAD for the parts to be laser cut, This is for (Three) reasons.(One) offer to those that do not have the skills or equipment to make the difficult parts need and to be accurate. (Two) To offer a part that would be lower cost than one can make on there own (Three) Have a Locomotive that one can buy and know that there is forward movement that the hobby can see that I am this for the long run.

Have I built a equalize Mogul or Consolidation yet NO, but I will and knowing that other have and made it work is enough for me to trust what Gene Design or offer was correct. Adding weight to the front truck is not a answer. The correct procedure and time spent to adjust the springs and positions of the Equalizer bar is the work need for each builder to have a fine running engine that tracking correctly.

So these new parts will be add to the web site and hope those that are setting on the fence will make the move for more Locomotive to hit our club tracks. There is a lot of thing in the works at Allen Models. This is just one of a dozen that on the list for more Steam Locomotives to hit the tracks and keep ( Steam Alive) Thank You from Allen Models and what to assure all that we are here to stay. Thank You Steve Alley

[NP317]

Steve:
I recently noticed the addition of cast iron parts instead of aluminum. Way to go!
I wish they had been available when I built my Ten Wheeler. I did machine some steel replacements for some of the aluminum parts, connecting rods included.
I'll keep watching your web site for more good changes.
Your approach to improvements is appreciated.

And now that I have my new lathe and milling machine (and shop!) set up and working, I'm hoping my winter projects can include changing my Ten Wheeler valve gear to the Baker set-up, using the castings and plans you sold me!
Fun machining ahead...

It's good to watch Allen Models survive and improve.
~RN

[Solar1953]

Bill Shields, I'd like to take a look at the underside of your lead truck to see how you attached your equalizing bar, if you don't mind. Thanks

[Raymbo]

I appreciate Steve Alley responding with what he is doing with the Allen line now. We do not have machine tools at all, I built all of the stuff we run with hand tools, a drill press, and table saw. The Mogul my friend bought was already built, some of the workmanship was very good on it. The Stephenson valve gear is difficult to time up, and it would be nice to change it to the Baker as suggested by RN, but without the tooling it would not be possible for us.

Same with the lead truck. Attempting to build and install the equalizing gear without tooling presents more than a few problems so adding the weight to the truck castings seemed to me to be the only option. Now that it is working we are pleased with it.

The engine is still slippery, probably added to by the increase of spring I put it, but it isn't w whole lot different. I would expect the engine to pull more on a flat land railroad for sure.

I appreciate all the responses on this thread.

RG

[little giant]

The Allen model consolidation has an equalizing bar connected to first set of drivers and then to the front pilot truck. Mine has worked fantastic I don't think it ever derailed yet.? Can Steve or other mogul users consider modifying their trucks the same way? I think the Allen fitsburg northern has he same type of front truck as well and Locoparts used to sell a completed front truck.

[Pontiacguy1]

A built-to-the-plans Allen Mogul is going to be somewhat slippery anyway. They typically weigh about 400 pounds. Unless you have more than 100 pounds on the lead truck, you're probably not experiencing more slip than is typical for this locomotive. They have pretty good size cylinders for the size of the locomotive. Gene Allen himself told me that an Allen American would pull all it was going to pull with 80 PSI on the boiler. I don't think it would be very much higher pressure for a 'stock' Mogul. That's why so many people weight them down a lot with thicker/heavier boilers, solid steel frames, steel rods, steel cabs, ballast, etc... They have more than enough power to put the extra adhesion to good use.

Also, the type of throttle used can contribute to the feeling of the locomotive being very slippery. I rebuilt/refurbished/reboilered an Allen 4-4-0 which had the original Allen type dome throttle that used the bronze casting with the sliding plate, which I re-used on the new boiler. It took careful use of that throttle to make the locomotive start with a load and not spin. The throttle seemed to open so quickly that it would just break loose and start spinning easily. You could pull a pretty darn decent load with that locomotive, even on 3% grades, but you just had to be careful with the throttle lever.

Also, note the shape of your wheels and flanges. If you have flat wheels instead of the typical 2 degree taper, they will slip more. Wheel profile, weight on drivers, and also your timing on the locomotive. The farther out of time it is, the more it is going to want to start slipping at one particular point during the rotation of the drive wheels.

I would also point out: Although I think an equalized lead truck is best and I would personally build it that way, there have been dozens upon dozens of these locomotives built over several decades with the non-equalized lead truck, and most of them don't have derailment problems with the lead truck, at least not anything more than what is fairly normal.

Just a few suggestions/comments by me. I'm not there and I can't see the locomotive in action so these are basically just some guesses at this point. Wish you luck with it.