Local travel news this morning referred to an earlier derailment causing delays to Reigate - Gatwick and Redhill - Tonbridge services. At the moment (08:00) there is a GWR unit stationary on the Tonbridge line south of Redhill (which is highly unusual), with a Southern unit at a stand beyond it. These are either on the up running line, or possibly on the adjacent siding. The down Tonbridge line is evidently clear, as a Southern service has just departed that way. Does anyone have more info' on what happened, and particularly how a GWR unit apparently ended up heading towards Tonbridge?