In answer to thethread title.
Is Open Access abstractive or does it genuinely plug gaps?
Yes.
OAO will "take" passengers from the main operator.
For example Dave takes the 08:04 to get him to work for 9am. A new OAO starts a new service at 07:46 and due to various factors Dave uses the new service and so is a "loss" to the main operator.
However, that doesn't always mean that the operator is financially worse off.
For example having seen the marketing for the new OAO both Claire and Sam look to travel along the route of the new service, and book onto the train which best suits their needs - which happens to be the one run by the main operator.
In an ideal world there would be no gaps for OAO to implement new services. As the main operators would test a few new stations for a few years with marketing andthe like to try and grow a market, sticking with those which work and scaling back from those which didn't.
The issue is that the DfT can't (or more probably aren't allowed to) do this, in such a world then OAO are a useful tool in increasing the number of passengers.
Given the low access charges that open access operators are charged, far below the fully burdened costs of those paths, I personally can't see how they can be considered anything other than abstractive.
Track access charges only cover a fraction of Network Rail's costs after all (last I checked it was ~25%).
Which is a fair point, up to a point.
However, the first question is which NR costs do the OAO only cover 25% of?
From the Rail industry finance report:
Network Rail
Operating costs: £3.3bn
Maintenance: £2.5bn
Renewals: £3.7bn
Financing costs: £2.5bn
Other costs: £0.4bn
Total: £12.4bn
The two values which are key are the Maintenance (i.e. direct harm done by each train) costs which are covered by the track access charges and the Renewals (i.e. long term replacement of life expired equipment).
The 25% figure quoted by rail unions is slightly skewed to make the OAO look worse than they are, but it's still something worth being aware of.
OAO pay all their track access charges (Maintenance), but (as I understand it, but maybe I've miss undersood something) effectively 25p in the £1 for the Renewals from their fixed payment (a per train cost).
Therefore, if every train was OAO the table would be:
Maintenance: £2.5bn - £2.5bn received (100%)
Renewals: £3.7bn - £0.925bn received (25%)
Total £6.2bn - £3.425 received (55%)
Given that they do pay 100% of their track access charges, so presumably do cover all their direct harm (maintenance) costs, I'm not sure how else to understand the 25% figure other than being their share of the Renewals budget.
Of course, the fact that not all OAO even pay this fee (in fact currently only one) muddies the waters in something which isn't a clear binary case to start with.
I'm in two minds about open access. On the one hand it can plug gaps such as London-Hull or London-Stirling, and the competition can reduce fares and increase ridership like we saw in Italy between Trenitalia and Italo as well as in Spain between RENFE, Ouigo and Iryo, and in France between SNCF and Trenitalia. Even Eurostar might well end up with lower fares with Virgin entering the picture.
But on the other hand, railways by their nature are a bit more constrained than airlines and road transport, and competition will only really be a select few cherry-picked routes (the notable examples I cited are all high-yield high-speed routes like Paris-Lyon or Madrid-Barcelona) because obviously when you're accepting all the revenue risk, you need to maximise your return on investment.
Ideologically I think rail should be a public service first, but pragmatically open access can work for the benefit of the passenger. If the space is available then I suppose it's fine really, but you could still arguably claim open access is abstractive if it's competing with a state-operator like Lumo and LNER on high-yield routes like London-Edinburgh. The WCML equivalent would be London-Manchester.
I'm minded to agree, OAO aren't a perfect situation, but then they are a useful tool in a rail model which is constrained in such a way which means that is unable to deliver even a near perfect perfect situation.
Obviously, there will be those from either side who will upsell the advantages or disadvantages of OAO's, the bottom line is that they exist, they do create services which often wouldn't exist, they do take passengers who were previously using TOC services, they do create positive headlines for the rail industry and it appears that they mostly grow the market overall. There are other things which they do which are "bad*", for example barring access to final salary pensions schemes for new entrants.
(* again whilst not ideal, for anyone moving their from a TOC this is going to be a calculation they take on a personal level, it maybe they've maxed the value they can get and so move for the last few years of working to create a second pension pot which they can use to further increase their income within retirement, it maybe that they can live somewhere cheaper and not need to own a second car in their household and so can use that spare money to pay down their mortgage and be mortgage free sooner, or many other things).
On balance, I would suggest that it's probably fair to say that "they are a necessary evil" is something many could accept as a fair assessment that many could accept as a view a significant majority would include as part of their position (i.e. anything more positive than this would include that, and it's only those with views of OAO's which are worse, for example from "I can't quite reach they are a necessary evil" through to "OAO are so foul they need to be sent straight to the same place as [insert something so bad it needs to be removed not only from this universe but throughout the multiverse]"