This was the name of a newly constructed military railway halt between Remy (Lijssenthoek) and Poperinge. The name was an invented one, given in the style of local Flemish place names. As it was used principally for offloading of troops arriving for service in the Ypres area, it is believed that was a British joke, a play on the words “hop out (here)”.
The yellow cross marks the location of Hopoutre. Another important halt was made at Peselhoek, top of this map.
This map of July 1918 shows the railway line coming up from Remy (below the map) and bending to cross the Steenvoorde to Poperinge road. Just north of the road, where the siding is shown, is Hopoutre. Note the “Leene” inn: it was also known as “In der Leene Cabaret”. It is still on this site, seen by the many visitors who go to the large military cemetery at Remy Farm (Lijssenthoek).
No sign of the railway or the Hopoutre siding today, although the line of the old railway from can be traced by the building of the modern (red) road which took its place. The line to Hopoutre curved off to the left of what is now a small lake.
Gazetteer of the Western Front