The group consists of four tram and light rail organisations located in four cities and the group is currently growing. The current list of participating members is below.
The participating organisations are:
- Berliner Verkehrsbetriebe (Straßenbahn, Berlin)
- Trikken i Oslo (Sporveien, Oslo)
- Brussels Tramway (Société des Transports Intercommunaux de Bruxelles – STIB, Brussels)
- Light Rail Transit (MTR Corporation Limited, Hong Kong)