Diesel cars are of little use in this game because their capacity is so small and they must carry kerosene. The suggestion is that if it were upgraded to a train (which would only involve connecting one or more trailers), its usefulness would be greatly enhanced. In an advanced city, trains can be used to collect more materials from afar to get home.
the other method is to enlarge the capacity of the diesel car.
I think a long train would be hard to make, but it would be cool if you could expand it with some kind of trunk at the back, maybe with a small box or even the baskets or backpacks, so it would work kinda like a horse, an item that looks like it’s 2 tiles but actually is just 1.
I like your idea. Recently, I would like more industrial evolution in the game. For me, I prefer a horse cart rather than a diesel car to find more material in farther places. A dirsel car has to be loaded at least one kerosene.
So we would go faraway more often and bring back material if a diesel car can be update.
Maybe we can upgrade the diesel car into something useful by adding removable steel hoes to make it a ploughing machine, or adding oil tanks filled with water to make it a watering machine. Even though my town reaches the highest tech tree, I often find it laborsome planting large fields of milkweeds, etc. In this way, we can make use of the diesel car, and enjoying farming more in the game XD. Driving over soil!!!