This from Danny Nelms:

the 1959 mack magirus ladder assigned to ladder 10 (E-150) was seen this weekend at the ATCA (Antique Truck Club of America) show in Macungie, PA. photos by Sam Guners

per the detailed listing from old shops records it shows assignments as:
1959 Mack B85F/Magirus 100′ rear mount aerial
Truck Co. 10
(07/28/1959 – 04/15/1962)
Truck Co. 30 (listed as a short term spare no further info)
(04/15/1962 – 11/16/1962)
Truck Co. 10
(11/16/1962 – 01/05/1969)
vintage former Chicago FD 1959 Mack / Magirus aerial ladder

photo by Sam Guners