Re: Today's picture

Those are the equalizing tanks that Dan Ranger wrote about. These tanks are an integral part of the locomotive brake system.

The basic concept of the brake system is that the engineer does not directly reduce the air pressure in the train pipe to activate the brakes. Instead the engineer’s valve is used to reduce the air pressure only in the equalizing tank. The distributing valve using its equalizing piston and valve does the actual work of making the reduction in the train pipe. When a reduction is made to the pressure in the equalizing tank this pressure imbalance causes the piston in the distributing valve to move and the valve uncovers a vent that causes the air to escape from the train pipe; when the two pressures become equal the piston and slide moves and the vent is closed.

The distributing valve is the device mounted below the cab beneath the lettering “D&RGW”, “D&SNG” or “C&TS.”

Brian Norden