The trolley-wheels used on the MER which are cast from phosphor bronze, are 4 ½” in diameter with a ½” diameter hole bored through the centre to take a spindle. They weigh approximately 2 lbs.
All of
the MER's trolley-wheels tend to wear slightly heavier on one side,
and at one time it was practice to reverse the wheels at about half
life. For some considerable time, the MER had old trolley-wheels
melted down at the Steam Packet's foundry and made into truck bearing
pads and other useful components, as well as being recast into
trolley wheels.
Until
1977 all of the Winter Saloon cars carried a “Sleet Wheel”
in their toolboxes as a matter of routine. The 'Sleet Wheel' is a special trolley-wheel with slits
machined in the cheeks, and were used to cut through ice on the overhead
wire. The presence of air frost on the wire is indicated by an
intense blue arc at the trolley-wheel.
