Over the course of the escort war, Civilian Roadsteamer production has diminished as manpower and resources reallocated elsewhere with a decent percentage going into Battlesteamer production. Never the less it did not fully die away while testing continued (in no small part due to the common mechanisms of Battlesteamers and Roadsteamers and the screen that it offered to Battlesteamer development). In 36 IA work began on a new type of Roadsteamer for limited production. The result of their efforts was the Series 12 Roadsteamer Lorry.
Weighing in at 3.5 tonnes unloaded the Series-12 used a fair number of components which saw use in Battlesteamer use, from it's piston assembly for it's rear wheel drive to it's helical boiler, which allowed it to raise enough steam to get going in about thirty second as opposed to the minutes required for previous models. Pneumatic rubber tires has also been a considerable boon. It's total engine output is 26 kilowatts and it's top speed is 48 km/h (unloaded and on paved roads). These vehicles can burn either alcohol or petroleum derived kerosene, though as of 37 IA this has only been done for test purposes given the expense of importing it.
The first working Series 12 Lorry was completed two days before the Battle of Daagsgrad for road trials and after a month of minor adjustments was approved for limited production, with an initial batch of ten ordered. Subsequent units would have various small adjustments made on them based on reports from reports form their users. They soon became popular with their crews and drivers, even though there was some frustration relating to tires going flat. Windshield wipers are a particularly well received. With Valnothron suing for peace another 100 were ordered for the next two years by the Central Committee with workers, engineers and machinery being sent back to the manufacture of these new vehicles.