The mode, described as "gladiatorial cart combat," will operate like the previous payload mode--but rather than one team attempting to push a mine cart to a finish line, both will be tasked with doing so simultaneously. The first map for Payload Race appears to be titled "Pipeline." A document written by Valve (above, right) notes that if players stop pushing the cart "for a sec," it will roll down to the bottom of the ramp.

Valve has also revealed that the update will bring two new Arena maps: Sawmill and Nucleus.

Of Sawmill, Valve writes: "Set in a stormy mountain sawmill, this arena map has its cap point in a large structure atop a hill in the center of the map; beneath which lies a hidden underground spytech base; and above which, pouring down on everything we just mentioned, is rain--the first weather effect to appear in a TF map."

Nucleus will feature a "diabolical doomsday device" set in the foundation of a circular map. The arena features "long sightlines and a bottomless radioactive pit underneath most of the game area."

The update will hit in a matter of days, according to Valve.