Class J lubricator ?

[NW Mailing List]

I was looking through the archive photos of the Class J trying to find 
engines with two lubricators on the engineer's side. I found that some 
engines had two lubricators, while some only had one and others had only 
one but with an empty bracket where a second lubricator had been.
Can anyone say why there were differences between the engines?

Jimmy Lisle