Thanks, Kelly. That’s exactly what I was looking for. I did learn quite a bit on this one.
J.R.

Very interesting thread, informative. Have not been personally involved with tires or much wheel work but have watched a little from the distance. One of the many things I find interesting if not amazing is the power of a "interference fit". When I saw my first tires removed and later reinstalled it was like magic. I had seen this before in industry when I was a welder but not on RR wheels and equipment. You think of a locomotive large or small pounding through tight corners or high speed makes you want to bolt them on for safe measure. Was involved in installing a new axle in the Polson #2 by way of interference fit. Am here to tell you those wheels are not going anywhere, at least moving or sliding on the axle. Of course they are keyed, but the force of the interference fit is unreal. We did not use a wheel press.

A privately owned {leased} locomotive which used to run at Mid Continent received new tires at Chattanooga. The cast iron wheels had been problematic with tires slipping in the past. We had extra tires for the locomotive but apparently could not use them. The wheels had to be trued up like Kelly suggests and then I suppose the inside diameter of the tires may have been to large? We had solved the slippage of the tires with shims long ago, but there must be specs that say go/no go? Thought I read somewhere that this particular type of wheel was an older design and had a number of "splits" and custom wedges had to be made in the process? I may try to find the link on that wedge subject and post it here. Not trying to get off topic to much but it is still wheel work and relates to tires and wheels. Do not recall if the new tires were stepped on this or not? C&NW #1385 received new tires at Strasburg recently and don't recall hearing of anything to unusual on those. One new crankpin I think, not related.

Thanks to all for this thread. I like these kind. Regards, John.

PS: on link below if you enlarge the pictures you can see the wedges or spacers in the wheel rim. they are not painted and can be seen. Don't have any close ups on it. Hope this isn't considered off topic but just another aspect of keeping tires on wheels I would think?
http://www.midcontinent.org/driving-wheels-completed/

The divided rims had to do with foundry practice in the early 1900's and wasn't related to the tire fit. The thinking at the time was that casting the wheel center with those splits in the rim would reduce casting stress. That was later found to be untrue, and rims were then cast in one piece. #475 has divided rims, and when we needed new wheel centers cast, the foundry man objected to having them on the new castings, so the replacements have one piece rims (I'm certain that somewhere there is a railfan who will now demand a boycott of SRC due to our lack of regard to #475's historic fabric).

FRA rule 230.114(a) requires that divided rims have filler blocks installed and maintained in the splits to make the rim continuous.

I recently dealt with an example of a redundant securement for locomotive tires. In this case on the engine truck axle on NH&I #40 with 30" tires and 22" wheel centers. The tire flanges were extremely sharp, tread worn hollow and 1" (yes 1 full inch) difference in diameter between left and right (don't ask me, it was like that when I found it). The tires were shrunk onto the wheel centers, but also had an additional mechanical securement. The wheel center had about a 1" by 1" rabbet groove cut around the outer corner. Into that fit a matching internal flange on the tire. The wheel center rim and tire flange were drilled through and reamed for tapered wrought iron bolts inserted from the rear of the wheel center with heads riveted into countersinks in the wheel center and nutted on the face of the tire.

Considering that FOMAS (formerly Ajax Rolled Ring) doesn't have any trouble hitting the 0.026" interference needed on the 22" wheel centers, I decided to do away with the added step of bolting the tires on. I ordered a steel ring 1 1/4" thick and faced one side and bored it to shrink into the rabbet on the wheel center. When both rings were installed I mounted the wheel set in the lathe and turned the wheel center and ring to the same diameter and then faced the ring flush with the wheel center. Standard wide flange tires could then be ordered with the internal lip for back to back location, thus changing over to only a shrink fit securement method.

20160610_130619 by Brendan Zeigler, on Flickr
You can see the rabbet in this picture with the steel ring machined and ready to shrink on.

IMG_2713 by Brendan Zeigler, on Flickr
Wheel set in the lathe, tire seats have been turned and faced, journals are being polished in this pictures. Notice the groove near the outside of the tire seat where the ring meets the wheel center.

20160929_144152 by Brendan Zeigler, on Flickr
Tire is shrunk on. You can see the unused bolt holes on the back of the wheel center.

IMG_2725 by Brendan Zeigler, on Flickr
Notice the ring inside the tire, differentiated from the cast iron wheel center by the shiny finish.

IMG_2724 by Brendan Zeigler, on Flickr
Completed wheel set.

Brendan Zeigler

Brendan,

Nice work on that lead truck wheel set. What is the size of the Monarch? 24 x 60?

Howard P.

I found Kelly's comment about the back-to-back changing under load to be very interesting; I had a similar experience as a teenager working for the Family Welding/ Trailer Hitch Shop ( M + M Shop, Glendale CA) in the 1970's!

One day we needed to replace the axle on a house trailer as failed bearings had damager the axle ends. My Dad told me to be careful about with bend in the middle of the otherwise straight piece of 2" square steel.

Being a car-crazy teenager, I was very careful to set it up with positive camber, as was done with race cars. This meant that the tires leaned inward at the top, so when going around a corner, the outside wheel, which sees the most weight, tends to square-up to the road, resulting in the beast possible lateral traction..

I had to turn it over when he told me that the bend was actually intended to cancel out the downward flex in the middle of the axle when under load, just as Kelly described! The trailer tires were supposed to lean out at the top when not under load!

Note that on a steam locomotive, as the axle rotates, the flex is cyclic for each evolution; no wonder why axles sometimes develop cracks or even break. On the trailer of course, the flex might be a little different on curves, bumps, etc. but wheel rotation is not a factor.

Our big William Tod stationary steam engine has a 20' dia. flywheel that weighs 60 tons. It is attached to the middle of a 23" diameter crankshaft with bearings about ten feet apart. So with 60 tons suspended on that shaft, I often wondered about the flexing that the shaft is taking.

Actually one manufacturer did make their bearings that sat in spherical sockets in the bedplates to accommodate the flex, but everyone else must have though that to be superfluous.

BTW, what really blows my mind is that the J&L 58 with all its heft doesn't even weigh as much as the crankshaft of the Tod Engine!

Some Diesel locomotives have shrunk on tires. Warner Bros. Van Sciver Plant #11 by Baldwin, later on New Hope & Ivyland RR had a shrunk on tire that moved inward.
There are stories that Pennsylvania RR locomotives #1 through 7, bought from the Great Northern in 1956, were so powerful that they could spin their drivers out of their tires. Secondary clips were later added.

Thanks Howard. It was an interesting part of the project. The Monarch is a 24" x 72" built in 1938.

Brendan

GG-1 motors also had tires. There were timetable special instructions limiting the use of the independant brake so as to not overheat the tires. They could and did come off!
Keith