Complex sentence: The high demand has led ScotRail to increase some services to three or four carriage trains, although this and the general opening of the line has also contributed to there being a general shortage of train carriages across the ScotRail network, leading to hiring of extra trains.
Split into simpler sentences: The high demand has led ScotRail to increase some services to three or four carriage trains. However this and the general opening of the line have also contributed to there being a general shortage of train carriages across the ScotRail network, leading to them hiring extra trains.