GWR adjust their timetable? You don't seem to understand how timetable planning works.
GWR don't just go to Network Rail and say, 'we're going to do x, y and z, so there'.
As Clarence Yard says, it all has to be agreed, for the fairly obvious reason that there are all sorts of other passenger and freight services out there and they all have to work together. Network Rail is meant to co-ordinate the whole process. Unfortunately, its centralisation of timetable planning work at Milton Keynes a few years ago cost it a lot of experienced staff based elsewhere in the country who did not want to move, which has led to serious problems.
In the GWR area, the belated admission that Crossrail will not meet its opening target dates for the tunnel under central London has done nothing to assist the process, as this has knock-on effects in terms of what Thames Valley services GWR has to continue to operate in the meantime and how its traincrew can be used as a result.
So the 18.50 off Worcester was timetabled to reach Paddington at 20.57 for a while. What exactly does this prove? I expect most passengers from Worcester would still prefer a 21.05 London arrival to sitting at Moreton-in-Marsh for 15 minutes and then sitting at Oxford for 10 more, before reaching Paddington around 21.30.
Some extra running time was applied to a number of evening fast services from Oxford into Paddington a year ago - it is not an adjustment this coming week, as you seem to think. I don't know whether this was at Network Rail or Crossrail's request for engineering purposes or to allow some extra time at stations to deal with slam doors in case of HSTs being used on these services instead of trains fitted with power doors and having the acceleration of a 180 or IET during the transition to full IET operation this year.
But it was not intended to be a long-term measure for the reason already stated above - that GWR was expecting to have its new IET timetable in place next week. When Network Rail finally gets its act together on timetabling, then there will be quicker journey times.
