Ömazislav/Gorganstien Delticron (Bus)

The Ömazislav Delticron, later referred to as the Gorganstien Delticron, is a line of intercity and commuter motorcoaches and transit buses that come in nominal lengths of 35' rigid, 40' rigid, and 60' articulated. They were initially made as 35 and 40 foot rigid buses by Ömazislav Otobüs from 1967 to 1979. From 1981 to 2002, the Czechoslovak-Turkish Gorganstien Otobüs subsidiary of Gorganstien trucks (which was formed from the remains of Ömazislav Otobüs after their acquisition by Gorganstien Trucks) took over production of the buses and introduced a 60 foot articulated variant alongside the 35 and 40 foot buses. In addition to the various lengths available, the buses are marketed with a variety of engine technologies, initially beginning under production by Ömazislav Otobüs with gasoline, conventional diesel, and diesel-electric hybrid; Later buses by Gorganstien Otobüs added more powertrain options such as compressed natural gas (CNG) and battery electric.

The original Delticron was based, in particular, on the GM "old-look" transit bus and was directly adapted from the GM TDH-5108 body style. With a steeper windshield and the option to remove the middle door, the Delticron distinguished itself from the GM "old-look" more than the Saribus did. Delticron buses were typically powered by the Detroit Diesel 6-71 inline six-cylinder diesel engine or the Detroit Diesel 4-71, a four-cylinder version of the same diesel engine, with the 4-71 being used for shorter variants. Occasionally, however, they were also propelled by a Tatra diesel or a Mercedes diesel engine.

The Delticron was designed primarily for transit usage, but it also differs substantially from the "old-look" in that, while being 40 feet long, it can accommodate 81 passengers instead of 51 thanks to a more flexible seating arrangement made possible by the removal of the middle door. A few Delticron models had lengths greater than 40 feet, and a few more models even had a "triangle 6" Napier Deltic-style engine, however these were rather prototypes and only three examples were produced. Only three of these small Deltic engines were created by D. Napier & Son under license for the three aforementioned specimens which were produced for the Soviet Union. This decision was coicidential; It was an unusual decision to put the Napier Deltic in the Delticron since the Napier Deltic 2-stroke diesel engine was originally used in Royal Navy high speed patrol boats and later adapted for use in railway locomotives. It rather happened due to a design revision made in 1971 which involved the switchover from the "old look" based chassis to a chassis that was taken from a truck chassis manufactured under license. Gorganstien had previously created a chassis to employ a reduced displacement version of the Napier Deltic as the sole power plant for an experimental truck chassis and the result was a deceptively strong medium-duty truck that can even tow road trains with little effort. To be adapted for use in the Delticron bus however, the bus body was modified to fit on the new chassis and the Deltic engine had to be moved to the back of the bus. However, because of the engine's high power-to-weight ratio, the powertrain was replaced with a special one consisting of high-ratio gearing between the engine and a special transmission specifically made for the engine by ZF, itself connecting to a pusher-style drivetrain. This resulted in the Delticron being the only bus in the world to solely be powered by a Napier Deltic engine until the Neoplan Deltomatic overtook it in 1987, which was powered by the same displacment Napier Deltic engine. Only with the Delticron II's debut in 1992 did the Delticron series recover popularity as a Deltic-powered bus. (On the other hand, the reason why the Deltic ended up in the truck was due to the fact that a turbo-diesel would be the perfect engine choice because the truck was intended to run on a high-power, lightweight diesel engine, but because this was the 1970s, such an engine wouldn't be that common; nonetheless, the fact that Omazislav selected Gorganstien as a chassis supplier for its Delticron series is also a coincidence because Gorganstien would later acquire Ömazislav Otobüs in 1979.)