Patent ID: 6910427

Claim:
A railway tank car having a manway formed in an upper portion of the tank car, the tank car comprising; a manway cover coupled to the manway; at least one valve coupled to the manway cover and operable to discharge fluids from the tank car; a protective housing assembly coupled to the upper portion of the railway tank car and disposed around the manway cover and valve; the protective housing assembly having a normal access cover operable to prevent unauthorized access to the manway cover and the at least one valve; the normal access cover having a first, closed position which prevents unauthorized access to the manway cover and the at least one valve; the normal access cover having a second, open position which allows access to the manway cover and the at least one valve; at least one porthole formed in a side wall of the protective housing assembly; the porthole providing access to operate the at least one valve; a porthole cover having a first position which blocks access through the porthole to the valve and a second position which allows access through the porthole to the valve; the porthole cover engaged with the normal access cover to prevent movement of the porthole cover to its second position when the access cover is in its first position; and the normal access cover allowing movement of the porthole cover to its second position when the normal access cover is in its second position.