Bridgeport started using the letters of the alphabet many years ago after the street pull boxes were eliminated
The letters starting with A indicated the first due response district
A - Adam Engine 1
B - Baker Engine 2 (now closed) but still use for assignment
C - Charlie Engine 3
D - David Engine 4
E - Edward Engine 5 closed
F - Frank Engine 6
G - George Engine 7
H - Henry Engine 8 closed
I - India Engine 9 closed
J - John Engine 10
K - King Engine 11 closed
L - Lou Engine 12
There never was an Engine 13
M - Mary Engine 14 closed
N - Nancy Engine 15
O - Otto Engine 16
Most of the closing of those companies took place in the 1990s after Bridgeport had their own set of heavy fire activity in the 1980s following the FDNY War Years of the 1970
The number following the Letter, in this case 3 (George 3 assignment) just includes the normal 1st, 2nd, and 3rd due companies