On 22/03/2024 16:52, TP wrote:
> I've no doubt that there are design issues on different models of

> trams that have a bearing on the problem.

Axle loads are a key issue.

In Melbourne, the fixed truck D2s have a maximum axle load of 22.2 tonne
(for the centre truck - 11.1 tonne per axle)

The Es are longer and heavier but have four swivelling trucks with a
highest axle load of 17.4 tonne (for an end truck - 8.7 tonne per axle)

The Cs have a quite high axle load - around 21 tonne per fixed truck -
fairly evenly spread across the trucks.

One of the key specs for the E class was for a lower axle load than the
C and D classes.

Mal Rowe - getting technical