The invention relates to a slide valve (20) having a slide valve plate (32) movable in a slide valve rail (29) between a locked position and an open position in a slide valve casing (26), said slide valve rail (29) being provided with a slide valve seal for attaining a gas-proof locked position, said slide valve rail (29) being connected to the slide valve casing (26) via a flange connection in such a manner that the slide valve rail (29) is removable from the slide valve casing (26) radially to a flow axis of the slide valve (20).