I have often talked about the fact that as a child I was fortunate enough to ride along on Saturdays in one of the milk wagons from my Dad's dairy. In the winter there was a small paraffin burner in those wagons to keep the milk from freezing. It seemed likely to me that the Mennonites might also employ heaters of that sort, but apparently not. I have spoken to many people who say that especially in a double covered carriage like the one in this painting, the interior is quite cozy just from the body heat of the passengers.