A ten car
IET▸ is 260 metres long ... and the ship we are on - the "Aurora" is 270 metres long.
Melksham to London is 100 miles and costs up to 88p per mile in the peak, down to 28p per mile super off peak. Our round trip from Southampton to New York is around 8000 miles and is costing us about 60p per mile, but that does include food, limited drinks (tea, coffee, water) and sleeper service.
As an alternative comparison, if the train averages 80 m.p.h and the boat averages 25 m.p.h., the train costs 70p per minute (peak), 22p per minute super off peak, and the boat is costing us 15p per minute ... but then our time in 10 ports is gratis.
The length may be similar, but the width and height vary. Aurora has a 32 metre beam, whereas an IET has a beam of 2.7 metres - so 12 trains would fit across the ship. The height of a train is 3.8 metres, but Aurora is some 60 metres tall - 8 metres of that below the water line - so you could stack 15 IETs (in diesel mode) on top of each other. In other words, Aurora is the volume of 180 IETs.
A ten car IET is staffed by perhaps 4 or 5 team members (bare minimum 3), to which we should add engineers, cleaners, etc, who do not travel with the train. Crew on the Aurora is 850 including those engineers and cleaners who in this case travel "with". Our IET has a seated capacity of 630; Aurora takes 1850. However, comparing an IET staff to passenger ratio of 1 to 125 to Aurora's staff to passenger ratio of 1 to 2.4 is misleading - cut the 1 to 125 to (say) 1 to 60 to allow for the none-travelling staff, and then again by a factor of 2.5 (making it 1 to 24) to allow for shifts - bearing in mind that ship's staff work very long hours. So we still have 10 times the staff per passenger on the boat than we have on the train; many of them are low paid and it would be interesting to factor in average hourly pay rates too ... if any members would care to develop this I would be very interested. We also need to consider shore and station staff, etc.
I know that some forum members are not thrilled by having diesel engines under the passenger accommodations of trains - I have seen them described as "unsuitable for long distance travel". And I muse that our ship is powered by diesel engines underneath the passenger accommodation.
With the different volumetric characteristics of the boat, catering can be somewhat more that a trolley. Let me share a buffet breakfast with you
Perhaps that's not your choice? Let's have a look at just some of the counters: