Surely it depends on the capacity of the route to absorb the number of services.
In the South East certain routes are pretty much at capacity both in terms of number of services and just as importantly the length of trains the infrastructure can support without huge remodelling of terminal stations (i.e. somewhere around 10 or 12 carriages depending on length.) Certainly in the morning peak the number of services is required to carry the number of people even with the longest sensible train lengths. If the trains exist and the marginal cost of running them in quieter times of the day is fairly low for an EMU then a frequent service makes it more appealing for occasional passengers who arguably give more revenue per journey than season ticket holders.
Other parts of the country not so much. Running 3/6 or even 5 carriage trains in areas where the infrastructure is pretty much to its maximum capacity in terms of trains per hour (e.g. Castleford corridor) is arguably not a sensible system
I agree with the above.
I've no problem with the frequencies on the old Southern Region since many of these services run at the maximum (ten/twelve coach) length permitted by the infrastructure and most of these services provide a simply patterned timetable to a London terminus...
(Ideal world, I'd tidy up some of the routes so that some lines get 100% of their services going to one terminus rather than a handful to Canon Street and a handful to Charing Cross, or a handful to Victoria and a handful to London Bridge, but this is me quibbling)
...but on the "Provincial" network, many services are much shorter than the infrastructure and we keep cramming
more trains onto lines rather than
longer trains in existing paths.
Take Leeds - York via Garforth (the route that is apparently too busy for XC to be permitted to run additional four/five coach Voyagers that way).
Leeds and York can take full InterCity length trains but (other than the hourly XC service) the longest trains are generally three coaches long.
We could have used resources to lengthen existing services, but instead we have found paths for Northern to double their service (so that the existing Preston - York service is sped up with an hourly "stopper" introduced to serve the intermediate stations). Similarly TPE have increased in recent times from three trains per hour (Newcastle, Middlesbrough, Scarborough) to four (doubling the Newcastle service, initially introduced as a service that didn't run north of York).
So the Northern/TPE service has gone up from four per hour (plus hourly XC) to six per hour (plus hourly XC).
Why? Because the two TOCs want to compete for a bigger slice of the ORCATS "pot" and because there's an obsession with running direct services over long distances.
Same problem in Manchester, where Oxford Road is being swamped with thirteen passenger services per hour (plus freight) because of the "need" to give everywhere a direct Manchester Airport link. But, because these are generally long distance services through Oxford Road, they are badly co-ordinated so you can end up with a ten/fifteen minute wait (e.g. xx:54 - xx:09 eastbound).
It's chicken and egg though - people want direct services because they think that changing trains is unreliable but one of the reasons why changing trains is unreliable is that there are so many services fighting their way onto a busy network (which means dwell times are poor because a two coach DMU only has four doors, rather than a longer trains which could accommodate more people in a shorter time).
And then you come on here and see people agitating for direct links between places hundreds of miles apart (because they don't want to have to change trains). I get that changing trains will put some people off and there are certain people who would only countenance a direct service but it feels like the tail wagging the dog - we are so focussed on the minority of passengers doing the irregular long distance journeys (where changing trains may be a fact of life, but these inexperienced travellers are reluctant to change trains) rather than having simple reliable well-spaced services on separate routes (but clock-face and regular enough to make changing relatively simple).
The world might not come to an end - which seems a strange metric for whether a particular service is sensible to run but hey ho
In fairness, the "world might not come to an end" seems to be the default defence of Brexit by people who promised us Sunny Uplands a couple of years ago and are now ordering body bags and warning of food shortages!
