When these conditions were achieved, the steam supply for the turbine generator was to be closed off.
As speeds and distances increased, mechanisms were developed that injected thick mineral oil into the steam supply.
The steam supply was controlled by an outside Allan valve gear.
A return spring returns the piston to its rest position as soon as the steam supply is interrupted.
As they move out from the central post, they close the steam supply more firmly.
Recently, the 1979 plant was decommissioned due to decrease in steam supply.
It ran in limited service in the 1990s sharing a steam supply with the stationary exhibits.
This required the use of a throttle valve in the steam supply, controlled by the governor.
In September he recommended throttling the steam supply to the engine.
In both cases, a steam supply was already available for other purposes.