Initial outlay is a lot. Easier to do post flybe collapse but covid has meant most operators are in financially turbulent.
Or the risk verses return isn't worth it. Could be profitable but there might be better uses for that money, like a competitor to eurostar (random thought, they charge a lot with not great service).
Reasonable answers, both of which are 'basic economics'.
Could a Penzance/Swansea-Bristol Parkway-Newcastle-Edinburgh-Glasgow* sleeper service be run?
Sure.
But it will need to have someone (government, presumably) fund the costs of:
- say 25 sleeping cars (5 Penzance-Bristol portion (1 x RLO; 1 x FO; 2 x SLE; 1 x SLED) 5 Swansea-Cardiff-Bristol portion = 10 northbound, same southbound plus spares, though perhaps the numbers could be mitigated if fully integrated with the existing CS pool),
- capital costs at Bristol to allow for the routine shunting of occupied rolling stock,
- and the purchase/hire/refurbishment of diesels/electrics (2 x Type 4/5 diesels plus 2 x class 90/91/92 plus spares),
- set up costs and operating losses for 18-24 months to allow the business to make an operating profit in year 3. (I can't imagine it would ever be profitable, and less likely still that it would be profitable enough to pay back the capital costs of the investment.)
So, it begs the question that we began with; not
could this be done (it could, relatively easily given a large enough budget), but is it a high enough public spending (and specifically transport spending) priority to make it happen? And transparently, no it is not, becuase otherwise the government would be shouting it from the rooftops
and actually doing it.
*At a minimum of 669m 48ch or thereabouts, this is some trip end-to-end! (In fact, this is Railmiles shortest, so in practice it would likely be further, especially if you swapped to electric haulage in Birmingham).