Why not ? I mean people will understand what it is they are paying for... People paid £100k for Virgin Galactic flights back in 2005... it's not carrying passengers yet. there's two ways to look at this.. 1. Inflation makes the ticket bidding attractive now for future passengers 2. The group gets money it needs now (which saves inflation costs on materials later). I would run the auction over a long period though, maybe even a year (granted it may turn stale for a while but the price will only go up). If it's successful you could run multiple auctions (i.e. 1st train, 1st mainline, 1st foot plate experience etc etc). the Class 15 diesel group did something like this a few years back for a cab ride on D8233 when it's complete, with a caveat that the actual date is open ended.