Wiki (
https://en.wikipedia.org/wiki/Island_Line,_Isle_of_Wight) states that...
"
passenger numbers ... have fallen rapidly to an estimated 1.31 million in 2014–15. This is the lowest annual estimate since 1998–99, and suggests passenger numbers have fallen by 22% in the last four years"
One thing I'd like to know is why passenger numbers are falling on this line when nationally they have been rising so rapidly elsewhere. What is different about Island Line? What unusual circumstances are there? Are there any other lines where passenger numbers have actually been falling, and if so, can any common circumstances be identified? Has something happened in the last few years to make Island Line less attractive? Are connections to it poorer than they were a few years ago?
The answer to those questions might give clues to what should be done about the line. Indeed, if passenger numbers are behaving so differently on this route compared to the rest of the country, then it would seem absurd to take any decisions about the future of the line based on those passenger numbers without first trying to find out what is causing that difference.
So, looking at RTT for the Esplanade, there's 66 services a day during the week, 66 services a day on a Saturday and 46 services a day on a Sunday.
442 services per week, so 22,984 journeys per year.
That's fifty seven passengers per journey. Enough to fill a single decker bus, with a handful standing, but certainly not enough for a single carriage 153.
Assuming those Wikipedia figures are correct: It's perhaps worth pointing out that 57 passengers/service on average will mean somewhat fewer passengers on a train at any one time (because not all passengers are travelling end-to-end). Even so, that doesn't seem too unreasonable to me for a 2-car ex-underground stock.
However, I think a more interesting question is this: It's reasonable to suppose that on average, each passenger is contributing between £2 and £3 revenue for a single journey (if you take into account through journeys from the mainland, it could be higher, but let's ignore that for now). That means that on average, each train journey is probably picking up about £150ish in revenue.
It's been stated a few times that the line is not viable because the subsidy is 80%. If that figure is correct (I haven't verified it), then that implies the cost of each train journey is about £750 (with £600 being covered by a subsidy). And that seems astonishing to me. Why on Earth would a 24-minute journey cost anything like that to run? For half an hour, staff costs can't be more than about £50ish. There'll be some admin. The trains are nearly 100 years old, so there can't be any capital costs associated with them. Yes, some maintenance to the trains and the line. But £750 for half an hour????? Or, with 2 trains running, £1500 to maintain the trains and line for half an hour? I don't know much about railway finances, but something seems wrong to me there. Are my calculations, and the figures they're based on correct? If so, then maybe, that's the thing that needs looking into?