Talk about facing a firing squad. Can't believe i was 2 back then

Did only Leyland RMs have Simms Electrical equipment? I have heard that there was more problems with electrical equipment on the Leyland RMs.

Not only Leyland engines had Simms electrical equipment, some AEC engined buses also had it.
There were not " problems" with Simms, it just became obsolete.
There was a programme of conversion of some RMs to CAV equipment on overhaul, I'm sure Neil G has mentioned it before.

My bus number (if any): RTL 960, RMC 1458, RM 1585 and several RTs

Less than half of the Leyland RM`s had Simms equipment so those that did have it were in a minority.

Or, to put it another way there were many Leylands that didn`t have it and there were far more AEC engine Routemasters than Leylands that had Simms equipment including all of the RMC`s and the majority of the RML`s.

The first big batch of Leyland RM`s which ran up to the start of the RMC class had CAV electrics. The RMC`s and the next big batch of Leyland RM`s that followed on from the RMC`s both had the same type of Simms equipment. The final big Leyland batch were CAV.

The Simms equipment fitted to RML`s was of a different type to the RM`s.

As Brian said, there were some conversions of both RM`s and RML`s from Simms to CAV and these buses had their classification amended to a new sub-class.

Having worked at Mortlake Garage that had many Leyland RM`s with Simms electrics, I was never aware of particular problems and non-availability of buses for service wasn`t a Mortlake trait.