Complex sentence: Recently however, there has been a ongoing strike at Renold since September 2009, which supplies the gearboxes for Alstom's propulsion units, so delivery is expected to slow down a bit until the strike ends.
Split into simpler sentences: Recently however, there has been a ongoing strike at Renold since September 2009, which supplies the gearboxes for Alstom's propulsion units. Because of this, delivery was expected to slow down a bit until the strike ends.