I was curious as to how the drivers on the J&L 58 were held on, so I set up the fire ring today and took off one of the condemned tires from the "other" set of driver boxes that we have.

According to the Porter drawing that I have, it shows there to be no shoulder on the tire to keep it from sliding too far inward. A few people told me that there must be some other means of holding the tire on and that the shrink fit by itself would not be enough. So to figure it out for sure I took the tire off, and indeed there is no shoulder.

My question is, how common was it to affix tires with the shrink fit only? Was this something that was limited to small diameter drivers or perhaps to industrial locomotives? Was it a common Porter practice?

Not having the shoulder makes my life easier, as I can now just heat each driver up and move it out the 3/8" I need to regauge to 24" gauge. By the way, this is the first time that I've ever removed a driver tire, and in fact the first time that I have even seen it done. Even built the ring of fire. Not bad for a novice!

Hi,

I do not know why another way to hold the tire on would be needed. In my opinion (SWAG), the steel of the driver center and the steel of the tire would expand and shrink the same amount so a 0.0015 (max) interference fit (tire smaller than driver center) would still be enough.

I recall as a kid seeing Dad showing me a glass jar of something or other that the lid would not come off could get it to come off. He held just the metal jar top under hot water (keeping the jar as cold and dry as possible) and seeing the fact that although there was no visual way to see that the jar lid had expanded it came off with a slight spin.

I even used it on room temp stored model paint that had dried the lids to the jar.

Thanks for helping me recall an enjoyable experience with my Dad (died 1982).

Doug vV

Rick -

Does the Porter sheet specify the deep cut grooves in the tire ID? That plus the tool marks in the center should be enough to hold if the fit is accurate enough. Being an industrial plant engine under 24" gauge would put it outside the purview of ICC/FRA requirements.

The Porter print that I have is for the axle box and the center/tire interface is shown on the drawing for reference purposes. No specs.

Note the gouge mark on the center that was made by a torch. At first I thought it was odd to ha have a torch gouge there, but then I figured that they would just cut the old tires off instead of pressing them off. There are two gouge marks fairly close together, so I'm thinking that each one was caused by previous tires. So assuming two torched off tires plus the worn out one that I removed, that means this loco work out three driver tires in its 25 years of service. That is a LOT of running around, with most of it on tight curves.

I haven't had a problem with the shrink fit not holding on wheels down to a 4" diameter. The step in the tire bore makes it easy for setting the back-to-back dimensions of the tires. Without a step, tire stops would need to be set up to keep the tire from moving too far to the center and keep the tire decently straight. Stepped pieces of steel (3 evenly spaced around the rim) could be bolted to the inside of the rim to act as tire stops. On the small tires I have applied, I used 0.001" per inch diameter shrink fit. In the shrink fit tables provided by Ajax, a slightly larger shrink fit is used.


In talking with several people, the idea was that when measuring with spring calipers it could be possible to have enough variance in the measurement to obtain a good shrink fit on small wheels so a secondary measurement was used.

Here is a little video I made of removing a tire on the other #58 that is being worked on.

https://www.youtube.com/watch?v=I1EpBFebrfo

Shrink fit is all you need, shoulder or not. Somewhere I have specs for different standards of tire fitting, some with shoulders or other locating devices, and some without.

years ago I helped change tires on a Baldwin 2-8-2. Nominal driver sizes was 44 inches. There was no shoulder on the tires, just a shrink fit. It was common to torch off old worn tires. Faster than heating them and they were just scrap anyway. I have heard of tires breaking when shrunk on if the fit was too tight. Also heard that a dragging break shoe could heat up a tire enough for it to come off.

From a 3’ gauge perspective, whether it be a Porter, Lima (shay), or Baldwin, all either had tires or hubs with a step or a lip (although I am fuzzy on the Baldwin off hand). Another engine, a Stephenson product of 1887, I recall having a couple of locking bolts between the spokes into or against the inside of the tire. So, for me at least, I am baffled by what Rick has here. I’d be interested in what Strasburg has to say at this point. I just can’t imagine relying only on the shrink fit heading into a curve at speed, pounding against that outer rail.

Shrinkage fit of tires on wheel centers is standard practice. The amount of allowance for shrinkage depends on the diameter of the wheel center. A tire that is fit with the proper amount of interference will not come loose under NORMAL operating conditions. Manufacturers and railroads varied on methods of locating the wheel on the center with some using a straight bore and others machining a step into the tire. Some used additional retaining rings, and sometimes, clips were applied to the wheel center that overhung the tire to prevent them working off if they did come loose.

The danger of one coming loose is mainly from being overheated by use of the driver brakes. On long down grades the tires can become heated enough to expand and come loose. That is one reason engineers are trained to release or "bail off" the engine brakes after brake applications. Some railroads that operated in mountainous territory installed "mountain cocks" in the cab of the locomotives. This allowed communication to the driver brake cylinders to be cut off and any pressure in the cylinders released so that the engineer did not have to bail off the brakes after each application. The D&RGW, for one, applied these to many of their engines.

Here you go. Your mileage may vary. Sorry, had to do it...

This is a scan from the 1946 AAR Locomotive Tire Manual, Recommended Practice, adopted 1937 (edited and reprinted in 1946). Within the Manual, is the Standard for shrinkage allowance which was adopted in 1907 and revised in 1933. If there was a later revision reflected in the MSRP, I don't know about it.

Some roads welded tabs to the wheels to keep tires from slipping off but the vast majority did not.

shrinkage fit works fine, just make sure it doesnt go on sloppy. There may be a certain reason to NOT hard connect to the wheels, driver slippage may help prevent wheel damage, the tire takes the brunt, not the wheel. Replacing a tire is easier than having to replace the entire wheel.

I’d prefer that this stay on topic which is to discuss what is used in ADDITION to shrinkage to ensure the tire does not move in.

Having actually done this before and having a tire here in my shop from a 3’ gauge 36 ton shay, I can tell you there is a step on the hub and a match on the tire to ensure the tire does not move in. Having done Porter tires, I can tell you there was a lip. Actual first hand experience is what I’d like to see here, not an off hand “shrinkage is fine.”

A quick look at a locomotive dictionary and such shows a variety of means to ensure no movement of the tire whether it be a step, something riveted on, etc. More than shrinkage seems to be the norm, although the 1939 ICS indicates that there may or may not be a lip or step.

In searching for Kelly’s updates here on RyPN, it looks like they have tires with lips on some of the equipment they have worked on. The Silver Dollar #504 comes to mind from one of Kelly’s updates, but no good shots of its tires. The hubs look to be smooth.

Stathi I think it was indicated via an older RyPN post that his Porter had no lip or step. That’s good information and what I’d be looking for.

I happen to have some photos of tires from a Porter air motor and sure enough there is no lip nor step. I never took the tires off my Porter, so no idea if they had a lip or not.

We seem to be finding that some engines had lips/steps/bolts/etc while others did not. For me at least this falls under the heading of “you learn something new every day.”

I still can’t imagine the 46 ton #58 banging its way around the steel plant with only shrinkage keeping the gauge correct, but as I said, you learn something new every day.

J.R. May

Hi,

From my lice steam days (7.5" gauge), I had a box car with steel axles and aluminum cast wheels. I used a keyway to keep the wheel from turning on the axle.

I do not know if this was ever tried on larger narrow gauges.

Doug vV

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