Drivers and Pumps
The driver wheels on the Y6a Class engines were not very tall, as what you needed from them was to be able to drag the heavy strings of coal cars at a constant speed. And since the wheels were smaller, you could build a larger boiler and firebox that would still clear the tunnels on the rail line. The steam operated air pumps are just above the drivers left of center.
Exposure adjustments made.
Drivers and Pumps
The driver wheels on the Y6a Class engines were not very tall, as what you needed from them was to be able to drag the heavy strings of coal cars at a constant speed. And since the wheels were smaller, you could build a larger boiler and firebox that would still clear the tunnels on the rail line. The steam operated air pumps are just above the drivers left of center.
Exposure adjustments made.