Typically seen on Express duties in the Yorkshire area - Leeds, York, Harrogate etc. Also occasionally used on the Trans-Pennine route to cover when necessary.
The Class 158 is DCC Compatible but is not provided with a socket or plug. Common opinion is that a lot of work is required to install a decoder to this model.
Information on installing a DCC Decoder to a Class 158 can be found by clicking on the following link http://www.bachmann.co.uk/pdfs/issue8.pdf