It had started heading towards Bristol. I assume that this happened at Taunton. I suspect there are some red faces somewhere and an investigation happening.
Was once on a train from Taunton booked to call Westbury sent up relief to Cogload propelled over up main to up relief crossover then off to Athelney with no delay , so short term planned. I thought we only did that at Swindon Panel! Don't feel so bad now. I very much doubt there will be much of an investigation into this, likely the signaller will be asked what happened, admit to wrong routing and asked not to do it again. It happens frequently enough that there are procedures in place in the rules for it to be corrected quickly without a huge fuss being made, any delay will have been down to a the time taken for the driver to walk the length of the train twice, possibly including being stopped by passengers multiple times and b the need to provide a space in front of the wrong direction movement in case the driver goes further than instructed so there is no risk of conflicting movements, stick on a few minutes for the signaller to talk to the Driver on the GSMR times and 20 minutes is pretty good.
Assuming no engineering works and a path being available, of course. It eventually reversed and went on its journey up the Waverley line. Taking a wrong route because by the time you saw the route indication you had no chance of stopping, is a routine event.
It's usually either signaller error thought it was something else and set the route accordingly , or the train plan programmed into ARS or given to the box is at odds with the diagram given to the driver. It happens, and since under normal circumstances you can't pull off for an unsafe route, only an inconvenient one, it causes delay rather than risk. It only gets interesting if having taken the wrong route you either stay on it and just keep going, or it is an unsafe route for a passenger train, such as the HST which ended up in the MGR circuit at Ferrybridge?
If the driver of an electric train accepts the signalled misroute, it can be quite time-consuming to sort out.
