Multi-Traction and Double heading - (The Americans call it making a Consist)
Using Multi-traction you can link DCC locomotive addresses so that several locomotives can drive as one unit. This is the MTR option on the LH100 menu (MU if you have set the handset into English). There is also the DTR option for double heading (DH if you have set the handset into English). The film shows how to add and remove locos using Double Traction
The next film shows how to link more than two locomotives as a Multi-Traction:
With Multi-Traction and Double Heading all the locos must perform the same. If you can try to select locomotive that accelerate and deccelerate to the same speeds, otherwise one loco will drag the other and they will also put strain on the train that they are hauling - especially if you are using a banking loco. In modern image this is easier as the real railways tend to use identical locos when they use multi-traction.