Slippage Detection System for railway car wheels

Actually the E7 Decelostat and even the 1947 Budd rolloKron are basically ABS systems.
and the Acela does have the E7 Decelostats as do Bombardier and Alstom cars and Amfleet coaches.
the weak spot on such systems however is once all wheels slip the Decelostat does not know what to do, it can only act if one or two axles go haywire.
But even on a ABS equipped automobile, if you lock all wheels the car no longer knows what to do, it can only differentiate if one wheel still turns.

DutchRailnut wrote:Actually the E7 Decelostat and even the 1947 Budd rolloKron are basically ABS systems.
and the Acela does have the E7 Decelostats as do Bombardier and Alstom cars and Amfleet coaches.
the weak spot on such systems however is once all wheels slip the Decelostat does not know what to do, it can only act if one or two axles go haywire.
But even on a ABS equipped automobile, if you lock all wheels the car no longer knows what to do, it can only differentiate if one wheel still turns.

A decelostat does not work like the typical automative style ABS though. It will not rapidly pulse the brakes in order to keep the maximum braking effort without locking the wheel. All a decelostat will do is release the air pressure to stop the slide and then re-apply it. But this does not happen extremely fast. You talking several seconds. Hardly the same as an automotive hydraulic system where it happens in an almost instant. Pnuematic systems simply will not work that way.

That is why those systems are not refered to as ABS systems. They are anti slide systems.

Correct on pulsing, but that would not work on a free wheeling one ton wheel axle combination.
on Automotive systems the ABS works on individual wheels not on axles.
But it still is a basic ABS system despite your objections.

and the E7 decelostat can be used for both slip and slide as was done on the SPV's

DutchRailnut wrote:Correct on pulsing, but that would not work on a free wheeling one ton wheel axle combination.
on Automotive systems the ABS works on individual wheels not on axles.
But it still is a basic ABS system despite your objections.

It would obviously have to have some major changes to work the same way on train as it does on road vehicles because of the axle system, but that, in addition to the issues created by a brake system that works nothing like a typical automotive based hydraulic system or even like a truck's air brakes have kept them off of trains thus far.

You can rationalize it any way you want, it is still not an Anti Lock BrakeSystem. It does not work like a true ABS system and because of that, it's not classified as one and they are not refered to as such. They are known by the railroads, the FRA and the manufacturers themselves as anti slidesystems. A true ABS system rapidly pulses the brakes to keep them right at the point of maximum braking without slipping. An Anti-slide system does NOT work this way. Early systems simply released the brake cylinder pressure completley, then re-applied it to whatever setting you had the brakes. This served to stop the wheel from sliding. But it certainly did not help braking. In fact, it often made it worse. Because a sliding wheel at least has some drag to it. Newer systems can better and more rapidly release and reapply the pressure to the cylinders. But the data they recieve to do this is still only working off of an axle rotating or and axle not rotating. There is no inbetween. And even the most modern systems, like those found on the Acela for example do not know how to deal with locked axles. Once all the axles lock, the train is simply sliding out of control. If you go to full service, and the axles lock, it's going to release and re-apply the pressure to whatever pressure the brake cylinders apply at while in full service. It's not going to use less air to decrese the problem. Hardly an ABS system.

yawn

The proposed Slide Detect System could provide accuracy of wheel slide measurements about 0.2 degrees per one wheel revolution with car speed 100 miles/hour. I would like to repeat that we do not need any mechanical coupling with car axle.

I would like to get the number of "teeth" for Decelostat System to calculate accuracy for Decelostat.

Thanks to everybody.

Ask wabtec, us giving that kind of info would border on industrial espionage

DutchRailnut wrote:Ask wabtec, us giving that kind of info would border on industrial espionage

Is a question of a car wheel diameter also qualified as an industrial espionage?

LAL2009 wrote:

DutchRailnut wrote:Ask wabtec, us giving that kind of info would border on industrial espionage

Is a question of a car wheel diameter also qualified as an industrial espionage?

Neither is. We are employees of the end user of the product in question. And the question being asked does not involve anything "secret". Anybody can simply walk over to an Amtrak coach and count the number of teeth on the bearing cap. It's not like he was asking for software paramaters or anything that is normally not revealed to the end user.

In any event, an online forum is not a place i would want to get involved in this issue anyhow. I value my job a little too much.

LAL2009 wrote:

DutchRailnut wrote:Ask wabtec, us giving that kind of info would border on industrial espionage

Is a question of a car wheel diameter also qualified as an industrial espionage?

I'm no carman, but I'm pretty sure there's 4 or more different sizes of wheels on the different kinds of cars.

I can tell ya about traction motors! And lightbulbs!! but that's about as much use as I can be..

My great thanks to all.

As it was stated in my 1st posting from August 20, we are small OEM Company and do not have any railroad experience. Our thought was to adapt our technology for the railroad car to advance safety and reduce maintenance cost. Your direct and informative responses helped me to understand the existing technology (Decelostat) and room for improvement (intelligent Slide/Brake System with high frequency response, reliable, simple and inexpensive).

I did not make my mind yet about my company next step in the railroad life, but it could not be ask on the Forum and will need total assessment of our limited recourses.

Regards,
Leonard.

[email protected]

In slippery conditions a braked wheel-set that stopped rotating and the brakes are released may still stand still due to the friction force is so low that it is not force enough to force it rotating again and a flat spot will very quickly develop.
It is not possible to have fast release with air brakes to prevent flats. It must be some speedy actuator between the air brake gear and the calipers or brake shoes that reacts just before the wheel stand still. But it has to bee in combination with a doppler radar or simmilar device.