Hi Stu,
Others could explain the _benefits_ of SignalHeads vs. SignalMasts better than I, but inside the Dispatcher code, there are some unavoidable differences in the logic. I use SignalMasts, so I can test/debug issues with those more easily than SignalHeads. The goal should be for these differences to be transparent to the regular user, but we're not there yet.
As for direction sensors, I only use internal sensors. Dispatcher SETS these when allocating a section. If I've included these sensors in my SignalMast logic, this prevents two trains from trying to allocate the same block, as only one will have a clear aspect.
Note: I only include the direction sensors in SM logic for blocks that may be used by opposing trains.
I've no experience with hardware direction sensors.
HTH,
SteveT
