Well I hope this answes your question leigh. these were taken from www.nycsubway.org
"Diamond Jubilee" Token
1979-1980: 50 cents
Issued to commemorate the 75th anniversary of the subway in 1979. Mintage 5.8 million, with some rare errors without the hole punched.
In 1979, to celebrate the 75th anniversary of the IRT, the New York City Transit Authority, now under the jurisdiction of the state controlled Metropolitan Transportation Administration, jointly planned the celebrations. The MTA had a graphic designer from the J.C. Penney Company, William Bonell, present a draft of the Diamond Jubilee token. Osborne Coinage struck ten million in brass for general circulation concurrent with the Y-Cutout issue. 5,000 were struck in proof brass, from polished dies and made available to the public from the revenue office at 370 Jay Street. 10,000 pieces were struck in copper-nickel, but were never released, and are presumed destroyed. The Fifth Avenue Jewlery firm of H. Stern had a numbered edition of 250 made in 14-karat gold. The design includes a subway kiosk entrance on one side, and the 1904 subway car on the other, with a large diamond above. It is interesting to note that nowhere on the token does it say "Good for One Fare!" Due to the speed of manufacture, many were struck with off-center diamonds, and some are known as un-punched solids. An error also exists with the token made of two subway car designs, and no kiosk design!
Stay on the right 4' 8.5"