CBM: specialist in replacement parts for coaches, buses and trams Working with several thousand urban and intercity transport networks throughout the world, CBM a specialist in spare parts for coaches, buses and trams is today the leader in its sector.CBM: specialist in replacement parts for coaches, buses and trams Working with several thousand urban and intercity transport networks throughout the world, CBM a specialist in spare parts for coaches, buses and trams is today the leader in its sector.