86101 and 87002 were hired during the first week in November by DB Schenker for use on 1Q13, the GSM-R test train. This was touring the West Anglia area doing signal strength tests prior to the introduction of the Class 379 EMUs.
The train was electrically-hauled because it needed to visit Stansted Airport, and diesel trains are barred from there because they set off the fire/smoke alarms in the airport terminal building.