Not necessarily. Although the DC motors have commutators and brushes which make a bit more noise than the ac's slip rings, either of those would be drowned out by the drive pinions. The noise that the gears would make depends on their state of wear and whether the motors are nose hung or have quill drives, (even the newest EMU traction system generally have nose hung motors).
Slip rings????
Sorry thats completely wrong.
ALL UK EMU with AC motors are three phase ASYNCHRONOUS type (aka "squirrel cage"). There is no mechanical or electrical contact between stator and rotor, only induced magnetic field.
Slip rings are generally a feature of synchronous not asynchronous motors, and no GB EMU type has these.
SNCF is really the only serious user of synchronous motors, but even 373s have a-synchronous motors. I think I'm right in saing the only synchronous motor electric traction to have run in GB in recent years were the SNCF BB22200 used by RfD on tunnel freight. Nothing, if anything (?) before that nor since.
And I'm pretty sure we've had this discussion before.
--
Nick