Necessity being the mother of invention during the war, public transport had to keep going even though petroleum products such as diesel and petrol were in short supply. Many bus companies such as the Thames Valley Traction Company turned to converting their buses to run on coal gas. Some companies converted their Single Decker buses to use a system as shown in the picture above. It resembled that of having a barrage balloon tied on the roof.
On the other hand the more affluent members of society converted their cars to using coal gas, as I have demonstrated to what looks like having three or four ¾ sized bed spring mattresses on the roof of your car. This particular system did not last long as people found that they ran out of gas when they least expected it. Then it was a pain to get it refilled at the closest gas works.
The Thames Valley Traction Company how ever went for the trailer gas generator which was towed behind the bus, where a small fire heated the coal to generate the gas. It was obvious every so often the conductor on the bus would get off and stoke the fire. This system use used for the majority of the war, until such time that diesel fuel became easier to obtain. Of course the last bus home to Cookham Village left the Rialto cinema at 8:30 pm and would go through to High Wycombe.