That's interesting Super, this may be explained by the history of this loco, since posting the question I went on a bit of a google in search of knowledge.
Apparently the history behind this loco was pretty uninspiring, it was the 498th manufactured out of some 1,500+ over a 20 year period or so.
However what's made it special is that after being parked in a particular station after being taken out of service it was restored and is now used for journeys on a preserved railway. Until recently it was the only one of it's type to actually be in running condition and has served in many different special trips including some special 'orient express' run.
This explains why there are so many different variations out there as it reflects the different incarnations its been through during its preserved life apparently.
The only other running example recently came back to life and is the D51-200 in the Kyoto museum. Apparently that is due to start making special runs sometime in 2017 after another restoration to make it suitable for running on mainlines.
Amazing what you can find out through google these days
Apparently the history behind this loco was pretty uninspiring, it was the 498th manufactured out of some 1,500+ over a 20 year period or so.
However what's made it special is that after being parked in a particular station after being taken out of service it was restored and is now used for journeys on a preserved railway. Until recently it was the only one of it's type to actually be in running condition and has served in many different special trips including some special 'orient express' run.
This explains why there are so many different variations out there as it reflects the different incarnations its been through during its preserved life apparently.
The only other running example recently came back to life and is the D51-200 in the Kyoto museum. Apparently that is due to start making special runs sometime in 2017 after another restoration to make it suitable for running on mainlines.
Amazing what you can find out through google these days
Happily collecting things all my life...