The LNER Encyclopedia

In various photos of Tornado (and on bachmann's A1) it is fairly evident that the cab sides lean inwards and the tender is thinner than the cab of the locomotive.

Does anyone know why the A1's incorporated sloping cab sides and thin tenders?

I believe the Peppercorn cabs were wider at the base than the preseding Gresley & Thompson versions, taking fuller advantage of the then latest post WW2 version of the group-stndard loading gauge, but tthe width at the eaves had to be more restricted hence the inward lean of the upper sides.

You're asking the wrong question about the tenders, if you think about it. The vast majority of LNER tenders, including the non-corridor eight wheelers, had tanks that did not exceed the kind of width that allowed for both a side-projecting soleplate on which it was possible to get a foot (or toe) hold, and made it possible for the crew to see past the sides of the tender for reverse running, rather than having to lean out of the cab doorway to a dangerous extent. Only the small number of corridor tenders bulged to the full possible width, out of necessity in order to accommodate the crew passage-way and sufficient coal/water. It must have been considered that locos paired with corridor tenders were not likely to see much reverse running duty. I gather that Gresley did at one stage propose a full-width non-corridor tender to maximise capacity, but the running department were evidently not keen.

Ay up!

There is also the question of lookout from the cab as well. A sloping cabside would allow the crew to lean further out without fouling the loading gauge. The BR standards copied this feature for that reason.