© 2018 Boiler & Engineering Skills Training Trust
Extract 1 © MT276 detailing two different wheel profiles in use for steam locomotives and how they are used
Extract 2 © MT276 detailing two different wheel profiles in use for steam locomotives and how they are used
Extract 3 © MT276 detailing limits of wear
A typical Wear Measurement tool in use . See how the tool locates itself on the two datums of the back of the flange and the flange tip, which are two places where theoretically there will be no wear in service
LO2 - 1
The steel tyre is shrunk onto the wheel centre and enables worn surfaces to be re profiled several times before the tyre is finally cut off and scrapped, so the process can start again. Of course ALL the driving wheels must be identical diameter. LO3 - 1
The keyways for a two cylinder locomotive are set at ninety degrees so that four equal piston thrusts deliver a smooth turning movement to the wheel. The wheel is an interference fit on the axle and is secured in place by the fitting of a key
A crank-axle with wheels being re-profiled in an elderly large lathe. It is also possible to use modern machines like Ground Wheel Milling lathes but care must be taken to always use the axle centre as the datum
Pressing wheels onto an axle using a large hydraulic press. The operative is seen checking the back-to-back dimension as the wheel is forced on . Typical loads for such an operation are 100 tons
Diagram showing the four different methods of fastening tyres to wheels © MT276
Stud fixing can generate stress raisers in the tyre as it wears thin.
Rivetted tyre can generate weakness in the circumference of the tyre as it wears thin.
Shrunk tyre with Gibson ring needs special equipment to roll the Gibson ring into the groove on the back of the wheel
Shrunk tyre over lip (originated by Bulleid) is used on Standard Locomotives and is the best option taking up least space
Steam locomotive brake block made of high phosphorus cast iron rubbing against the steel tyre. The heat generated during braking can if prolonged loosen the shrink fit of the tyre which can lead to a dangerous situation whereby the wheels turn within the expanded tyre.
Rolling in a Gibson Ring forcing it to swell out and fill the groove at the back of the wheel and retain the tyre
Fractured axle. Regular ultrasonic examination of axles can detect incipient fatigue cracks which can lead to fracture, even though they are very shallow at first.
Locomotive on a low loader showing how easily wheels and axles and springs can be overloaded if long ramps are not used during loading and unloading
“Weighing a locomotive” This is really a misnomer because it really means getting the weight on each individual wheel to the required value so that no part of locomotive or track is strained.
The KELBUS equipment is installed on a straight and level track and the locomotive is physically lifted about half a mm off the rails by its flanges. Adjustment is carried out by altering the spring hanger length but each adjustment affects all the other readings.
Tyre Wear Gauge
It takes its reference from the rear of the wheel
Derailment caused by wheel fracture
Mk III Coach axle failure
Induction heating of the taper roller bearings prior to fitting to the tender axles
Click on the image for a report on a class 306 EMU axle failure
WHEELS & AXLES