I remember the first generation trams (after the airport tugs) and how they would belch black smoke into the air like a tractor pull. They had smokestacks that protruded from the back of the engine cover from the black ovals shown below. Anyone know if the current trams are the first generation tractors converted/ modified/ painted?Yes, they did this for a short time since the ferry boats could not keep up with demand. I think it was right before all of the monorails came on line. So maybe first month or so. Or I could have this backwards. I think it was also mentioned in Bob Gurr's video as well. So the tractors were designed to pull the trams up the 6% grade on the water bridge by Contemp. Initially they could not do this very well and would overheat regularly. This is why the design has not changed much from the orange/brown trams to current purple/white ones.
....goes to read Bob Gurr article to answer own question.
Yup. Second to the last paragraph, there it is. CNG to Diesel, back to CNG. Same trams for 40+ years.