The main line of the HLB originally was the Königstein Railway between Königstein and Frankfurt-Höchst of the former Frankfurt-Königsteiner Eisenbahn (Frankfurt-Königstein Railway, FKE), known as the K-Bahn and part of the Frankfurter Verkehrsverbund (Frankfurt Transport Association, FVV).

In the 1990s, the HLB subsidiaries operated a number of local lines acquired from Deutsche Bahn in north and middle Hesse.

Since 11 December 2005, HLB multiple units have operated on the Kahlgrund Railway from Hanau to Schöllkrippen in the Bavarian Spessart.

The KVG operates the Kassel–Waldkappel railway, which combines rail freight and tram traffic.

Through other subsidiaries the HLB operates passenger transport services beyond the Hessian borders in four of the six neighbouring states: Hessische Landesbahn is a member of the Tarifverband der Bundeseigenen und Nichtbundeseigenen Eisenbahnen in Deutschland (Fare association of federally and non-federally owned railways in Germany).