Towing The Transbus

I wasn't sure exactly what I was going to find at the Detroit Public Library's National Automotive Historical Collection's "Duplicates Sale", let alone if I was to find anything that would lend itself useful to this blog.

Somewhere between scroungning through boxes of Brazilian Chevrolet medium duties (to be posted shortly), and paging through 20 pristine copies of introductory brochures for the GMC General, I found a set of 8 photographs, all stapled underneath a photograph of an odd-looking frame.


Turns out, this frame has much to do with the forebears of the RTS bus....

The stack of photos, 9 in total, detail tests performed at GM's Milford Proving Grounds in 1974. The main purpose was to detail and evaluate a new towing system, designed for the prototypical Transbus design.



The tow system consisted of two frames. The lower frame was long and rectangular; it connected behind the front suspension, and also supported the bus just ahead of the front wheels.



The upper frame was "A"-shaped, and ran from the hitch of a tow truck, to connectors in the front bumper of the bus. What mounts this connected to is still unknown.




The remainder of the photos show the Transbus (towed by a Milford PG-owned GMC HI-9500) being lugged around sections of the track. No captions are included with these shots, so they're most definately internal engineering photographs.






Thanks to an apparently eager photographer, The (unofficial) GMT Blog is now able to display various shots and angles of this rarely-known prototype.



Conversely, we are also able to compare it to the similar-looking information regarding the RTX, GM's transit-bus prototype from 1968. While the body is virtually identical, the RTX differs in having tri-rectangular headlamps (similar to production RTS units), single turnsignals in the bumper grilles (as opposed to duals in the Transbus), and a full-length passenger compartment, thanks to the underfloor-mounted gas turbine engine.

And as for that opening photo - that was purchased seperately, but it is almost certain that it is of an RTX/Transbus prototype. Taken in the GM Truck & Coach engineering bays in Pontiac, MI, it's dated in 1970. The frame in the foreground bears the same welded-module assembly that the RTS carries, but also sports a lower step-in height. Look closely at the depth of the door/step of the rear door in the shot.

The (unofficial) GMT Blog is currently researching more into the background of the RTX, Transbus, and RTS. Additional information will be posted as it develops.