I do have a serious question though. Freight using the Wigan - Southport line is very good news since it is currently passenger only, while the Kirkby line isn’t, but what will happen in the event of 769s obstructing the passage of freight or vice versa and what is a pad as opposed to a siding?
I think that a pad is just a concrete or tarmacked apron that runs right up to the rails on one side of the line: it is large enough for forklifts to unload from a lorry, turn and load the goods on to the wagon, and for the lorry to turn and depart (or vice-versa). It doesn’t need to be very long as you can always move the train up wagon by wagon.
The loading would normally be done in the middle of the night or occasionally on Sunday mornings when there are long gaps between trains. The process of getting the train to the pad, handling the load, checking the wagons before departure and then getting the train to where it can be recessed can be very drawn out.
Pad is not to be confused with PAD: Pre-assembly depot. This was a civil engineer’s depot where points and crossing were prepared for being used to replace worn-out components. They would usually be laid out on the ground and very carefully measured to check they fitted the drawings for the location they were going to. They would then either be loaded complete on a wagon or carefully dismantled and taken to the site for relaying. (A simple description, there was other work done at a PAD.)