I've played World of Busdriver (also known as city bus simulator), which simulated the M42...it's the same thing with that simulator, they did a great job designing that RTS but the physics were absolutely terrible...you tap on the brakes and the bus stops from 50 to 0 in like 3 seconds
These games are rather demanding so make sure you have a powerful enough computer before you spend $$ on buying..there should be a trial version available on the web, go download that and see how its like before you pay