Mr Horton stated he recognised passengers' frustration
The boss of beleaguered rail agency Govia Thameslink Railway (GTR) is to resign.
Passengers have confronted main disruption as lots of of trains have been cancelled following the introduction of recent timetables in May.
GTR, which runs Thameslink, Southern and Great Northern, stated chief executive Charles Horton would stay in publish for a brief time to supervise the event a non permanent timetable.
The RMT stated: "The rotten franchise he was steering remains in place."
Announcing his resignation, Mr Horton stated: "I recognise that passengers have been vastly pissed off on the vital disruption brought on by the introduction of recent timetables.
"It is the right time to hand leadership of GTR to a new pair of hands."
RMT common secretary Mick Cash stated: "Mr Horton might now have gone however the rotten franchise he was steering stays in place and no change on the prime will alter that.
"This whole basket-case operation is a failure on every level."