Provided is a steam turbine in which, among a plurality of stages thereof, a stage that is disposed furthest upstream is a speed-adjusting stage, at least one stage that is disposed downstream of the speed-adjusting stage is a medium-pressure stage, and at least one stage that is disposed downstream of the medium-pressure stage is a low-pressure stage. The speed-adjusting stage is an impulse stage. The medium-pressure stage is a medium reaction degree impulse stage in which the degree of reaction is a medium degree of reaction of 10-40%. The low-pressure stage is a reaction stage having a higher degree of reaction than the medium-pressure stage.

A stator vane segment (100) of a fluid flow machine, having an upstream casing-side attachment (1) and/or a downstream casing-side attachment (3), and a platform (5). The attachments are provided on the platform (5). The platform (5) has a first sealing section (17) and extends in the direction of flow beyond a connection region (15) that connects the rearward attachment (3) to the platform (5). The first sealing section (17) that is located in a section (18) downstream of the connection region (15) has a first slot (19) which is continuous in the circumferential direction. The present invention also relates to a turbine having at least one stator vane segment (100).