Complex sentence: The S7 stock started running the full length of the H&C line to Barking on the 9th of December 2012 the Hammersmithand city line should be all S stocks by the end/mid 2013.
Split into simpler sentences: The S7 stock started running the full length of the H&C line to Barking on 9 December 2012. The Hammersmith and city line should be all S stocks by the end/mid 2013.