Why is East West Rail projected to be so slow?

[HSTEd]

The journey time given for MKC-Oxford over East West Rail is 45 minutes, when its only about 55km by rail.

That's about 45mph average speed, which seems a bit slow given the supposed nominal 100mph line speed and relative paucity of intermediate stops.

Is this just low performance diesel trains ruining everything again?

 

[The Planner]

Its only 100mph from Oxford Parkway to south of Bletchley, so about 26 miles / 41 km of it. Stops at Oxford Parkway, Bicester Village and Bletchley are going to do you for 7 or 8 minutes of that. Bletchley to MK will be a schlep regardless. Wires would make it quicker by a bit but nothing enormous.

 

[Ianno87]

Consider that today Oxford (depart)-Bicester Village (depart) is 19 minutes and Bletchley (arrive) to Milton Keynes (arrive) is another 6 minutes, that leaves 20 minutes for Bicester Village to Bletchley.

Which seems pretty reasonable for the distance (about 20 miles) and the one intermediate stop.

 

[stuu]

The journey time given for MKC-Oxford over East West Rail is 45 minutes, when its only about 55km by rail.

That's about 45mph average speed, which seems a bit slow given the supposed nominal 100mph line speed and relative paucity of intermediate stops.

Is this just low performance diesel trains ruining everything again?

Random comparison: Didcot-Slough is the same distance, the (electric) 2104 tonight takes 56 minutes although with 4 extra stops. 45 minutes doesn't seem particularly slow for that distance with 4 stops