At peak times on weekdays, you have 2 trains per hour between London & Swansea. From PAD - 15.45, 16.15, 16.45, 17.15. 17.45, 18.15, 18.45 & 19.15 all go through to Swansea.
In the morning peak, these departures leave Swansea for PAD:> 4.58,
05.27, 5.58, 6.28, 6.58, 7.28, 7.58, 8.28.
Oh, yes, wow. This now makes 4 hours of the total working day where two long trains an hour run. There are another 12 or 14 hours of the day when there is still only one long train running in each direction.
So, had they been able to get the wires through to Swansea, a considerable amount of money would have been saved by ordering electric trains instead of the hybrid versions - where the diesel engines will require on-going maintenance.
Why would money have been saved? Think a bit about the area served and the structure of the IEP deal.
The Great Western's route structure has always been very different from that of the routes to the North from London. In these cases there are large cities at each end of the routes (Glasgow, Edinburgh) and largish towns and cities between them. It is comparatively simple to run fixed length trains between them.
The Great Western's route structure resembles that of a fan, it has a large city at the pivot and although some large towns and cities are on the network they by no means lie in anything like a straight line and there is quite a lot of thinly populated country past the last city. The extremities of these routes are very unlikely ever to be able to generate enough traffic to carry the fixed costs of electrification.
This means that at some point in the journey a change of traction will be needed and, ideally, the train length will be matched to the traffic. In days gone by the GWR dropped sections of trains at Exeter or Newton Abbot for Torbay and Kingswear or left the restaurant cars at Plymouth and Worcester letting a shorter train go forward. Bi-modes are a technically appropriate answer to this issue and they come in two lengths which allow this type of operation to be used again. They also permit electric operation on the most densely trafficked parts of the route.
For reliable operation of a railway, or any transport business, the trains (or planes) will ideally be the same so there is no problem of substituting a different unit for a defective one. If one deliberately makes, in the case of the GW, one sub-group more restrictive in its area of operation - by making it electric-only -one is making a rod for one's own back.
As for spending money - the way the IEP deal is structured means that Agility Trains first receives payment when the first trains
enter revenue earning service. At the moment Agility Trains/Hitachi is carrying the whole cost of the design, development and manufacture of the trains and the cost of construction of the maintenance depots. This is why the deal is so eye-wateringly expensive - a very large proportion of the leasing costs will go on servicing Hitachi's debt which is needed to pay for all this before it starts receiving an income. Agility Trains also signed up to fulfilling diagrams, not supplying trains but fulfilling diagrams, with a very high degree of reliability. This means that more trains will be built than would be the case in a conventional ROSCO-type deal. Hitachi explained all this to a meeting of the IMechE a year or more ago and the lesson was that the capital cost of the train made very little difference to the lease costs over the 27.5 years of the contract from the date the trains enter service.
So, with or without the diesel engines, there would be little difference in lease costs.
You break the existing traffic flow (Taunton to Cardiff) because a change has taken place with electrification whereby it is desirable to operate a new electric flow Swansea > Bristol Temple Meads and switch the diesel service from Taunton to perhaps Gloucester. This helps justify the cost of electrification and removes dangerous fumes from the Severn tunnel as well as stations.
The railways are not there as somebody's toy train set - they are there to supply a need. If the traffic flow from (Points southwest) - Taunton - Bristol - Cardiff -(points west) is more significant than Taunton - Bristol - Gloucester then it is plain stupidity and bad business to turf the customers out at Bristol because of some perceived operating advantage.
The question of fumes is a red herring - in steam days it used to be a lot worse and nobody, to my knowledge died. All one did was close the windows to keep the smuts out. If the fumes from the little remaining diesel traffic are so bad then some more bi-modes of some variety (there is now a choice) could be leased.
Someone has commented that a Swansea to Bristol Temple Meads electric service would be part of the South Wales Metro and the responsibility of the Welsh Government. All well and good, but it is also a part of the Bristol commuter belt with many people travelling from say Severn Tunnel Junction to Temple Meads or Filton. Likewise, many people from these places commute to Cardiff or Newport. The fact is that the public are living where they can afford and consider time it takes to get to work and the transport facilities that are available. If you have clapped out overloaded Sprinters, then they are more likely to use their cars and jam up the M4 and M32. Modern electric trains on this route will help induce these people off the roads. They don’t give one toss who operates the trains or whether it is the south Wales Metro or the Bristol Metro. All they want are decent fast trains with plenty of space so that they do not have to stand.
Politicians from Cardiff, Newport & Bristol have been taking about co-operating on transport issues. I would contend that Swansea should also be included to form one ‘super region’ which could perhaps extend eastward to include Bath.
Yup - all good stuff. But has little to do with the case for extending the wires westward from Cardiff. A bi-mode can still reach Swansea, and indeed Carmarthen, from London and the passenger does even have to get out of his or her seat. It's not as if west Wales is being cut off.
Don't get me wrong - it would be nice to have electric operation the whole way. But warm and woolly arguments do not make a business, i.e., financial, case.