Then came renumberings and reformations within the Class, so they looked the same but may have a different number.....
...OK, I can cope with that.... They were 73xx and 74xx units when I were little but they got all computerised and were given 12xx and 13xx numbers. Then some became 'Greyhounds' and others didn't so they then became 17xx's and 18xx's as well but lost the 12xx numbers but the Greyhounds kept the 13xx numbers.
That just about made sense, cos at the end of the day, you could still tell from the side profile what it was originally, as you can tell from the above pic.
However.... The above pic was the back of the Unit and next comes a pic of the front. In the past, I have seen temporary reformed units, 7700 was such an example with one CIG driving trailer and three VEP coaches. But 1871 seems to want to go further. It obviously hankers after being a CEP but without changing coaches!
I sometimes wonder if I am losing the plot!