(21 Feb 2014, 5:58 pm)Dan wrote One in front probably broke down.
Or late, but it could also help with depot standardisation with them gointo Chester for the 34 (5251/5252/61/62), 28 (5263/4/5/6/7) and X25 (5268/9/70/71/72) allowing 8303/4/5/6 to go to Washington for the W5/W6.