Two of them are the bits that hang from the frame, but you have to look closely to see them.
Truth be told this is the first time I have put any underframe detail on any production Tin Car I've built because until now I'd always assumed that they sat so squat on their bogies that you couldn't really see anything.
(110 was a different case because it was built up on a central spine rather than the bulky ex-Isle of Man frames used on 117 onwards.)
When it came to this model I was looking at a photograph closely and I could just make out two things lurking underneath - which I presumed to a vacuum reservoir and a battery box - on the 'engine side' of the carriage.
Knowing that I am working for a very demanding client I had no option but to knock something up to represent them.
I think the next task will be something more obvious, the two sets of vacuum pipes.
Two sets? Yes, and if you don't know why that is I'm going to leave you in suspense until next time.