The Elizabeth Line service to Reading is not a all stopper but also a semi fast service within Greater London. Getting Elizabeth Line service doesn't mean the stopping pattern must be all stopper out of London.
Giving a through service to passengers west of Reading while having semi fast running pattern is the best of both worlds.
Isn't it difficult to be brief without being absolutely clear what one means? When I wrote 'stopping' I did not mean 'stopping at all stations' but trains which stop more often than not at the stations they pass.
There seems to be two schools of thought at play in this thread: (a) all Crossrail/Elizabeth line trains should call at all the stations between their origin and terminating points and (b) they could/should stop at selected stations only - at least during part of their itinerary.
Option (a) is the simplest to market but has the disadvantage that the journey time is increased for those places furthest from the centre. In the case of Reading this doesn't matter as there are many alternative trains which take less than half the time to reach London. The issue is more pressing for those separate settlements between Reading and, arguably, Slough which would/could have journey times to London which are less competitive than they could be - towns such as Twyford, Maidenhead and indeed Slough.
These are the towns which benefit for a reduced number of stops closer to London and the outer suburban service which used to run through to Oxford (now cut back to Didcot) did exactly this. It also permitted cross-Reading journeys such as Tilehurst to Twyford or Radley or Cholsey to Maidenhead to be made without changing trains.
Together with the two Elizabeth line trains per hour which terminate at Reading a four trains per hour service was possible for the principle stations out to Reading which is quite sufficient for the traffic on offer. In truth the Elizabeth line has not increased the service west of Maidenhead as it is essentially simply the re-badged 2 trains per hour suburban service which for many years has terminated at Reading.
The issue now is that the increased usage of the Relief Lines by the Crossrail/Elizabeth line trains closer to London means that it has become very difficult to path the Oxford trains on the Reliefs east of Reading and I understand that in future these will now run on the Mains from Dolphin Junction to Paddington.
This comes at a cost - it introduces a 40mph flat crossing move to and from the 125mph Mains with all the potential for interruption and delay that such a move brings with it. There are some ten or a dozen off-peak departures from Paddington which use the Mains and an equivalent number of Up trains. These semi-fast Didcot (and Oxford) trains must now be slotted into this pattern - and it is only possible because some Main Line paths have been freed because the non-stop Bristol - London trains will not be running for the foreseeable future.
For those wanting more Reading to London stopping services. It is worth remembering that the plan for a Western Access to Heathrow is on hold but will eventually make use of the relief lines to Langley.
Absolutely, one hopes that by the time it is operational TfL has built its own reserved tracks at least to Heathrow Airport Junction...
But this lack of knowledge or understanding of the realities of train operation seems inherent. Nobody has mentioned or acknowledged that pathing issues occur west of Reading as well and trying to fit more Crossrail/Elizabeth line trains onto the Reliefs will have knock-on effects further west. For example there is a roughly hourly container train in each direction from Southampton to the Midlands and points further north using the Reliefs from Reading West Junction to Didcot East Junction and on through Oxford. These are 750 metre long 75mph trains which take time to clear junctions and do not accelerate very quickly. Equally the Cross-Country trains through Reading also frequently use the Reliefs - which is why they are cleared for 100mph between Reading and Didcot. The passenger outer-suburban trains have to fit in with these patterns as well. Even changing times by a minute or so can have effects at Trafford Park...