The two lines remained in separate ownership until they both became part of the Swiss Federal Railways (SBB) on 10 June 1918, although the TTB had operated the WB from 1902.

This line was never a great success, and in 1948 much of it was abandoned, but the stretch from Hinwil to Bauma was acquired by the SBB, retained and electrified.

However passenger services ceased by 1979, and the Hinwil to Bauma section is now operated as a preserved railway by the Dampfbahn-Verein Zürcher Oberland (DVZO).

Einheitswagen ("standard coaches") I or II as well as a BDt or Bt control car made up the rest of the consist, all of which were generally in the NPZ (blue over white) livery.

In December 2006, THURBO, a regional railway partly owned by the SBB, took over the operation of the S26 passenger service and provided new rolling stock.