I work on the railway, I travel alot along the Birmingham-Wolverhampton route. I have done for around 10 years & I get to stare out of the window alot.
Between Sandwell & Dudley and Dudley Port Train Stations you can catch a glimpse of the Union Furnace Bridge and it's very noticable graffiti in large white capital letters TOJO THE DWARF.
Tojo is unknown, the age of the graffiti is unknown.