why are there differences in the interiors of trains of the same class?

[387star]

Why do same class interiors vary of older stock like 150s and 142s.

For example was it written in the North Western franchise document to retain bench seats on 142s as opposed to the Northern Spirit operation?

Was it down to ROSCO management?

Surely they were due a major overhaul at the same time.

Were some operators more prepared to invest?

 

[Schnellzug]

I think interior specification is entirely up to the TOC to decide; I suppose some have more money to spend than others.

 

[387star]

Another question:

Why did NX experimentally refurbish class 317s last year? They look really great

And have FCC refurbished class 319s which had the 'newer' Thameslink interior when the livery was changed to silver?
--- old post above --- --- new post below ---
Bit off topic but why did WAGN under PRISM refurbish their trains in a completely different interior style to the external livery

 

[swt_passenger]

Even under BR not all stock of the same class or type was delivered with identical interiors. The differences aren't all down to current practices by TOCs and Roscos...