Map Size: Small
Vehicle Map: No
Corrosion is one of the maps available in the second Call of Duty: World at War map pack.
According to callofduty.com:
In "Corrosion" face down your enemy in a deteriorated Russian train yard. Sprint under, over and through the shattered pipelines and war-torn train cars in this mid sized map great for full out team combat. Keep your head on a swivel as your enemy could be above or below you!