1. Wide units, TDH-4616 and 4518,totaled 273
2. Mechanical, 4-speed transmissions, TDM-4517 and -4519, totaled 14
The new-looks, first delivered in September 1959, were also known as "fishbowls" because of their much larger windows, especially the six-piece windshield, compared with predecessor buses. The fishbowl effect was quite startling to some people accustomed to seeing only small-windowed buses. In Dayton, Ohio, the first order was specially modified to use opaque fiberglass in the lower sections of the windshield to restore proper modesty to the Midwestern city.
Detail differences in the new-look appearance occurred in late 1962 when the art deco, square marker lights were changed to bullet-shaped lights anf other appearance details were changed along with several engineering improvements.
Another variation in the model number scheme occurred in 1960 when the new suburban configurations created the SDH and SDM types. When eight-cylinder engines became an option, the D in the model number was replaced by either a 6 or an 8, depending on the number of cylinders. The letters A or N at the end of a model number indicated either Air conditioning or No air conditioning.
Model designations were by nominal capacity (45) with the even-numbered models (4516, 4518) indicating the 102-inch width. Starting in 1968, model numbers of air conditioned buses ended in "A."
Information from the Bus World Encyclopedia of Buses - 1988