The regulator includes two elements:
The first one is the control
lever in the cabin.
The driver pulls the lever
to open the regulator.
Due to pressure and friction,
some effort is necessary.
A metallic stem, here removed during works,
links the lever to the sliding gate valve,
fitted on the dome.
This link from the driver's lever
passes trough a stuffing box sealing
the pressurized regulator.
It drives a sliding gate that
more or less covers an opening.
The steam comes from the rear round orifice
and exits to the bottom,
where a tubing brings it to the cylinders.
The sliding gate has a V shape
giving a progressive opening
for starts and manoeuvres.
