The LNER Encyclopedia

There was half a coach body in my neighbourhood in use as a garden shed.
I have found a number on it 2478 THIRD
Can anyone enlighten me as to what type and any probable history.
It seems it was part of a cluster of 7 bodies now it is the only one left (as of 2007)

We have a whole carriage down our road, don't know what it is though, but it's complete with wheels!