As the crossrail TBM is being disassembled today, I wondered about the following questions, can anybody help? 1. Is a TBM reusable on a different project, is it designed for one type of ground condition or is it totally knackered after one project? 2. Can a TBM of say UIC gauge be used to bore out say a W6 gauge tunnel or are there better techniques? 3, Can the cutting head be changed to suit different ground conditions? eg could the crossrail TBM be used to drive a new tunnel through the pennines? 4. Does the design of a TBM vary according to the ground conditions? eg crossrail goes through London clay, pennines are hard rock. 5. how does time taken to tunnel vary according to how hard the strata is? eg london clay soft (when wet anyway), pennines hard.