Colnbrook rail depot
As described it currently ends facing south. However, the plans for R3 were that it arrives at a new siding facing west, for material (maybe fuel as well), carbon offset etc.
Pre Covid a new contract was signed between a rail freight operator and a fuel company (Kent coast), probably to feed T5 satellite (not T6).
Of course another new line via tunnel is proposed from GW line to T5, £1bn +. Both lines will impact on rail capacity, freight trains are slower.