I just noticed this extra train has been added and I'm assuming its a 158 formed by removing the back 2 coaches from the 1509 arrival from Portsmouth (in a similar vein to the old through Portsmouth-Penzance train). Would that be correct and if not what stock does form it and why does it get over an hour from Westbury to Taunton non-stop and also 37 minutes from there to Exeter non-stop?