If you are going to need a guard for a gate, having a tank seems like a good idea. If that gate is named after one of the US Army's preeminent tank commanders in World War Two, than it is definitely appropriate. There was no information about exactly what kind of tank it was, but I believe it to be a WWII vintage Sherman tank. If that is correct, it was tanks like this one that was involved in nearly every major battle on the European front during the war. Having one outside West Point, seems like a fitting tribute.
Points of interest
This gate is named after a famous tank commander in WWII