Reading a copy of Nieuwsbrief Issue 84 of Spring 2013 it stated that some time SNCB needed to impose a 40 kph speed limit on line 37 between Verviers Central and Welkenraedt alongside the hill and tunnel near Dolhain Gileppe. This was due to the unstable condition of the adjacent hillside. Initially Infrabel considered closing the line but SNCB required it as a connection to LGV 3. As a result Infrabel have totally realigned it, building a new cut and cover new tunnel and abandoning the section alongside the hill and the old tunnel at a cost of 20 million euros. The section is now in service with an increased speed restriction of 100kph.
Credit to Benelux Railways Society