It has struck me that the aerial pic I just posted shows three different tramway operations in a small area.
I have marked them on the pic attached:
http://tdu.to/Operators_Aerial_StKilda_lookingSE_c1926_ErnestEbell.jpg
* Green marks the cable tramway built by the MT&O Co
* Blue marks the 5' 3" (1600mm) electric line built by the Victorian
Railways
* Red marks the standard gauge electric line built by the P&MTT.
Mal Rowe - noting that the VR line remained separate from the MMTB to the end.