allow a top speed of , more suitable for mainline use. Each unit was formed of two outer driving motors, with an additional intermediate motor in the 3-car units. The technical description of the formation is DMOCL+MOS+DMOS. Although still listed on the vehicle data sheets at DMCL vehicles, the first-class area has been removed from 2-car 165s operated by GWR. As such these vehicles are now technically DMOSL vehicles. The 3-car units were similarly de-classified, but the first-class accommodation has now been re-instated on these. Individual carriages are numbered as follows: 58953-58969 - DMCL 58879-58898 - DMOSL changed from DMCL in 2015 55415-55431 - MOS 58916-58932 and 58933-58952 - DMOS Unit 165115 was destroyed in the Ladbroke Grove rail crash. Accidents and incidents Ladbroke Grove rail crash: On 5 October 1999, unit 165115 passed a signal at danger while leaving London Paddington on a Thames Trains service. This resulted in a serious collision with a London-bound HST service. 31 people were killed and 417 were injured. On 30 June 2005, unit 165037 was approaching the Gerrards Cross Tunnel, which was under construction, when the driver realised that the line was blocked. An emergency stop was made and the train came to a halt before the tunnel, which had partially collapsed. The train returned wrong line to where the passengers were detrained. On 16 June 2016, unit 165124 was derailed by a set of trap points at after passing a signal at danger, causing significant disruption to services. The driver's assistant's side of the cab was destroyed after the train hit a stanchion that holds up the overhead catenary after derailing. The vehicle was moved after two days in position at Paddington to Old Oak Common Depot to be taken away by road for assessment and repair work. Unit 165128 was in service as a hybrid unit with 58609 (MOS vehicle from 166209) inserted in the middle from November 2015 until May 2016. This was due to one of its driving vehicles being damaged in an engine fire on the North Downs line in November 2015, rendering it out of service, and so to provide another 3-car train in service. On 21 June 2020, units 165015 and 165006 formed a passenger train at passed a signal at danger (a SPAD) and was in danger of colliding head-on with a passenger train formed of London Underground S stock at . The two