The new trains are being built wider than the current 1967 tube stock. This is because the Victoria line has a larger than normal loading gauge compared to the other deep level tube lines. The larger size means that the new trains cannot leave the Victoria line except by road as they are too wide to travel on the other London Underground deep level tube lines. This means that to move the units, each car has to be uncoupled, loaded onto a lorry, and then re-coupled when they are delivered. The trains have been built using Bombardier's technology called FICAS, which gives them a thinner bodyshell. Along with the larger size this gives more space for passengers.