And that's possible now thanks to CASR - 16tph both ways could be done if enough stock was available. I assume you don't mean 32 tph both ways?
Around 32 arrivals and 32 departures per hour. Heavy rail would be 11tph (4 from Penarth, 3 from Barry Island and 2 from Bridgend, plus 2tph to Radyr via Ninian Park). If we pretend that platform 8 became a bay platform for those services, 60 divided by 11 is 5.45 minutes to turn the train round and get it back out so the next one can take the platform. Platforms 7 and 8 would then be the terminus for light-rail services, which would come at a frequency of at least 16 per hour (probably more, 16 being 4tph each from the Treherbert, Aberdare, Merthyr and Rhymney lines). I think 16 trams per hour is a turnround time of 7.5 minutes with two platforms.
The approach of the Welsh Government to the Franchise and the 'Metro' is infuriating. As they always say Keep it Simple Stupid.
Valley Lines
* Electrify all routes including Vale of Glamorgan, Maesteg, Ebbw Vale, Marches
line to Abergavenny and Glouscester Line to Chepstow. Services to be initially
run with Class 315 shortened to three cars.
* Sort out ticketing - ITSO/Iff card, barriers, review prices.
* Extra parking - P&R at appropriate/new stations.
* Increased revenues to pay for new stock.
Simple, but problematic. The marches and Chepstow routes are not currently earmarked for electrification, and by 2023 (which now seems to be the target date for electrification) the 315s may have been scrapped (and 3-car might be less than needed at peak times, given most ValleyLines platforms are now able to take a 4-car 150 formation and some (Treherbert and Rhymney to Penarth, I think) can take 6-car 150s). There's also the problem of TSI-PRM compliance for the 150s and Pacers; there's no time to get the wires up, and if 150s are made compliant the ROSCO will probably require them to be kept beyond 2023 in order to recoup the investment in PRM mods, meaning unsuitable 150s on long journeys or delays to electrification until the 150s can be got-rid. And the Pacers need replacement anyway (Porterbrook's response to one of the consultations/inquiries suggests they've given up on ePacer following the Northern franchise outcome). New bi-modes could also delay full-electrification, and probably wouldn't arrive before 2020 (Anglia's deliveries are due to run into late 2019 I believe). Thus I would suggest:
- Bring in around 20 bi-mode 319s, which should be enough to replace the Pacers given some run as 4-car sets
- Order up some mrk5 coaches (probably the only new-build fleet possible by 2020) to create a cascade with 175s releasing 150s from routes such as Cardiff-Cheltenham for...
- ...forming into 4-car formations on the ValleyLines network, with around 20 units going for PRM mods and the remainder banned from working alone (is that allowed within the TSI-PRM rules?)
- Electrify from Barry to Pontypridd
- Order new 3-car and 4-car EMUs with UEGs and 20m vehicles (something like an Electrostar; better yet get the 379s from Anglia and off-load some of the vehicles to other TOCs to have a mix of 4-car and 3-car units come to Wales)
- Electrify the Ebbw Vale line, and Cardiff Central to Maesteg
- Electrify Cardiff Queen Street to Rhymney
- Introduce the new 3-car EMUs
- Electrify from Bridgend to Swansea, and if not done already get Bristol Parkway to Temple Meads wired
- Electrify from Pontypridd to Treherbert, Aberdare and Merthyr
- Introduce the new 4-car EMUs, cascading the 319s onto the Swanline and Cardiff-Cheltenham services (linked into a through service), plus new all-stops services to HEREFORD (absolutely NOT Abergavenny, because of the wider interchange potential at Hereford) and Chepstow. Also introduce a Cardiff-Bristol semi-fast service (replacing part of the Cardiff-Taunton service); for this reason at least some of the new EMUs must be outer-suburban (rather than inner-suburban), but I'm wondering whether the whole metro should be outer-suburban because of the possibility of long journeys between the valleys and Vale Of Glamorgan stations.
I've not put Cardiff Bay, Penarth and Coryton on the list for electrification, because they could perhaps be converted to tram (if they have their own street-running core section), but if not converted they must also be electrified.
The idea with the mix of 4-car units and 3-car ones is that the 3-car units could run as single-units off-peak on the routes with 4-car platforms, with the 4-car units running off-peak on 6-car routes. Then, in the peaks the 4-car units go on the 4-car routes with the 3-car units doubling up to make 6-car trains. Technically, the 4-car EMUs don't need UEGs, since they won't run in multiple (hence the 319s being ok); but future-proofing.
The 319s will be life-expired sooner than a new bi-mode, allowing an earlier oppertunity to get the routes to Hereford and Cheltenham electrified.
The only problems I can see are:
- whether the 319s on diesel mode can keep to current schedules while waiting for wires
- whether you can make the 319 interior 'outer-suburban' enough for the longer journeys from Swansea to Cheltenham and Cardiff to Hereford (the doors are 'inner-suburban' ones as the 150s have, and they're 20m vehicles), especially since the Cheltenham route would by that point be used to regional express 175s
- how you get the plan across to the Welsh Government and get them to agree to it
We can only hope that the bidder you mentioned that wants to keep the VL network heavy rail as is, is the most affordable and so winning bidder, even if it is Arriva.