Trucks and wheels - repair, replacement

[rockytop]

Got to thinking the other day about wheels and trucks - how often are they replaced, maintenance schedules, etc. Did a quick google search but it became apparent that I don't have enought information to limit a topic search. Obvious individual questions -

1) how often are trucks replaced
2) how often are trucks serviced
3) noticed the post about turning wheels - how often is that done or scheduled
4) I know there are devices for detecting hot bearings, but how often are the wheel bearings scheduled for maintenance or replacement
5) and on and on

this is just curosity on my part

Thanks

Charles

[ACLfan]

Charles, one repair item that you left out that accounts for a lot of service time is the servicing/replacement of traction motors. The replacement frequency depends significantly on an individual basis. In many cases, the "wear and tear" impacts of daily operations will have tremendous influence on how often a unit is in the shops for traction motor replacement.

ACLfan

[txbritt]

Things were done on a case by case basis at the locomotive shop at which I used to work. We'd check things like wheel condition ( flange/tread height, width, profile, etc.. ) Condition of the various wear plates, springs, rigging, and so on. If the wheels fell out of spec it was either turned or that one TM/Wheel assembly was replaced. TM's were replaced when they stopped working properly, usually when they started smoking. Simple things like journal and side wear plates were replaced directly on the truck ( while still under the locomotive ) by cutting out and welding in a new plate. Springs were a different matter as you had to have the truck out and the TM's removed to take the weight off. We didn't have a drop table so we hired a crane to lift either end of the locomotive, then we'd drag the truck out with a forklift, lower the loco onto jackstands, and perform the work. That or we had a spare truck already assembled and we'd just swap them there. All very interesting but extremely heavy work.

I guess I should note that I'm referring to the AAR Type B Truck.

TxBritt

[rockytop]

Thanks for the info -

to expand the topic a little bit - does anyone have any similar informtaion on freight and passenger trucks and wheels?

Charles

[EDM5970]

One of the professional journals had an interesting paper several years ago. When the C&NW started running the AC units in Powder River Basin coal service, basically 24/7 high adhesion operation, they were wearing about 1/32 inch of wheel tread away per month. (That 1/32 number stuck with me, for some reason.)

Now, thats in mainline service. If you have to squeak a C-420 or GP-40 into some industrial sidings with sharp curves, you will get some flange wear, but maybe not so much tread wear.

Depending on your usage, your mileage may vary. That is why wheels get inspected and turned or replaced as necessary, as opposed to being replaced on strictly a mileage basis, as TxBritt stated.

Also, there is a labor issue. If you are taking apart a "combo" (motor and wheelset), to replace a motor, and you have a wheelset that is marginal, it takes no more labor to replace the wheelset as well. On major railroads, and the better shortlines, they have spare combos in stock. I know of one good shortline that always has a rebuilt spare GP-9 truck, with rebuilt motors, ready to go on a moments notice.

[nickleinonen]

for trucks, we don't change them out until they are completely worn out... wheels we will turn down on the milling machines until they are TSTT [too small to turn]. if the wheel is somewhat ok [like 1.25-1.5" tread] we will build up a motor with that wheel if we need to, and when we do re-wheels [change out all the TM combos on a unit] we will keep some for use in another unit to keep the wheel sizes in balance [no more than 3/8" difference in tread difference within i truck, no more than 5/8" difference between trucks if i am remembering things right] to keep it FRA.....

we have 2 small drop tables that will handle tm change outs, and one big drop table where we can drop trucks & fuel tanks.. and we've got maybe 30 or so traction motors [various - d77-79, d87, d87-ars, d90, ge's] some are combos already, some are waiting to build...

building most combos are pretty easy and don't take too much time....

last year, my work mate and were working on a sd60 [d87-ars motors] and we removed, stripped [b/o motor ok wheels] and built up a new combo, and re installed it ready for electrical hook up in just under an hour...