Eddie, James Howard:
The more I think of it the more stupid is this fixation on a 10-minute DART service all day. On commuter routes just about everywhere, frequency (and capacity) is related to demand, i.e. to the morning and evening peaks mainly. LUAS is 3 to 4 minutes in the morning peak and anything from 6 to 15 minutes off-peak. That's the normal way of doing things everywhere, except apparently in the Wonderland of DART.
Even worse, a huge amount of money has been spent a few years ago enabling the operation of 8-carriage DARTs. Now the strategy seems to be for more frequent trains, very often 4 or 6 carriages. This is a straightforward waste of track capacity. James Howard refers to faster DART time making things more attractive for passengers. True, and it also enables more frequent trains. Trying to fit in very frequent trains and simultaneously timetabling slower trains is a very inefficient use of track capacity.
And having the same service interval between 8 and 9am as you have between 9 and 10pm is pure madness.