Did the articulated Steam Engines have 'dual throttles'?

The articulates had only one boiler as did any other steam engine. The steam was distributed evenly to all four cylinder piston assemblies. The leading driving wheels and pilot wheels were fixed to their own sub-frame which was flexible via a crescent shaped bolster receiver. This allowed lateral flexibility separate from the trailing drivers, while the boiler was rigid. They operated the same as any other steam engine. One throttle, one steam engine. Opening the throttle was simply allowing more steam pressure to enter four engine assemblies instead of two.