>>1691273>almost all locomotive hauled trains have been replaced with multiple units, leading to a ridiculous state of affairs where 4/5 car DMUs travel the entire length of the country for 13 hours straight.It's not as ridiculous as you'd think. DMU trains are more efficient than loco-hauled trains for passenger capacity, as if you put the traction equipment under the passenger compartment there's of course more space for passengers. If you're on about the total number of units that form a train, short trainsets can run more frequently than long trainsets; as shorter trainsets will of course have shorter dwell times at stations.
It's counter-intuitive, but, some boffin will have sat down and done the algebra.