Passenger Trains > Re NJT and wheells falling off

I just returned from 4 days on the NEC and read with interest the thread regarding NJT wheels falling off.

I can tell you from first hand experience that NJT equipment suffers severly from "flat wheels", and this applies to their brand news cars as well.

In my view, the steel used in these wheels must be of very poor quality. I don't actually know what causes "flat wheels", but wheel slipage caused by brake applications should not cause this if the steel is hard enough. Just imagine, brand new cars with very little mileage on them with flat wheels. The teriable vibration caused by this condition might contribute to eventual wheel failure or the wheel "falling off"

Amfleet cars also have this problem, but not as bad as they used to. Acela doesn't seem to have this problem---better steel maybe?

Wheels falling off is more often attributable to bearing failures than to flat spots. A bad flat spot usually will get a car sent to either the repair shop or a storage line, but a failing bearing may not be noticed until disaster strikes if there are no hot-axle detectors -- and sometimes a bearing can overheat between detectors even when such devices are present.

Flatspots are caused by way to agressive running during commuter runs.
The wheels are not hardened, they are cast steel. but with todays coaches being only half the weight of old standards and use of composition shoes the wheels slide sooner.
the old Heritage cars with Cast Shoes had way less problems with this.

Around Los Angeles a very high percentage of flat wheels is caused by failure to release hand brakes. Wheel slip/slide protection seems to work very well, trains make aggressive "parachute" stops without sliding. But I have seen crews drag consists around with a "light" handbrake left on and think nothing of it. Or move two consists into Union Station, tie both down with hand brakes, and the incoming crews forget to knock off the brakes.

The wheel failure last year was formally attributed to an overheated axle, as I recall. The problem was ID'd by a hotbox detector, but the test administered by a conductor didn't confirm the problem and the train was released to continue. (Conductor had to climb under the train and administer a flashlight sized device to the underside of the axle.)

There are reasonable differences of opinion about the training given to the conductor, about the efectiveness of the test, and about the alternatives (resume high speed, set off the car, annull the train, etc) considered.

Wheel flats are caused by sliding wheels, it does not matter what kind of steel is used, class A, B, or C wheels will get flats and shells from sliding. The wheels will slide from braking caused, usually, by crews dragging cars around the yard with the hand brakes on, or more often without HEP, and therefore no power to the slip slide system. Road failure of the slip slide system is another good reason. Small skid flats will cause a lot of racket, and vibration, but will most likely not effect the bearings. Large ones, over two inches, are real bangers, but even then they will have minor effect on the bearings.

However the bearings themselves will wear out or fail eventually. The grease seal fails and the lub leaks out, or the rollers spall or fret, or, in the case of the Arrow MU last year, the car grounds through the bearing and pits the rollers. Regardless, all roller bearings will fail eventually, you just have to replace them before they do. The fact that they have not had many failures in over 20 years of operation is an indication they are inspecting and replacing the bearings before they fail.

NJT's problem is not necessarily a maintenance issue, as it is an issue of a lack of hot bearing detectors. They have none. None on the right of way, and none on the cars, they do not even use smoke bombs. Without any detection for hot bearings, the eventual failure is not found until the thing burns off.

The Arrow's wheel was picked up by Amtrak's right of way HB detector. Had the conductor actually looked at the wheel the train would have been stopped right there, and limped back to someplace to change out the wheel set.

Also, as I understand, wheel age has little effect to "flat spots". Even sliding a brand new wheel at speed for a relatively short distance will do it in.