Re: Flat Wheels in Sydney

[James Robinson <NOSPAM@ERIE.NET>]

M.B. and C.M.McDonald wrote:
> 
> But ... what about non-motorised bogies?  Slip (power on)/slide (braking)
> ought to be easy enough to detect on motored axles by comparing electrical
> signals from each axle.  Come to think of it, shouldn't require too much
> additional equipment to detect slide on a non-motorised axle - some
> form of sensor which can relay axle speed to a controller.  However,
> controlling the braking _on that axle/bogie only_ may be another story!

Pneumatic/mechanical systems have been available since disc braked
equipment was first introduced in the late 1930s. Westinghouse Air
Brake's Rolokron is an example. These evolved into elecronic anti-slide
systems in the 1960s.  They are now applied to pretty well any high
performance passenger equipment.  The following web site is an example
of one product.  As suggested, a small alternator is applied to each
axle, and the electronics use this signal to compare axle speeds and
accelerations.  

http://www.knorrbrakecorp.com/slipslide.html