Thanks to all who responded. A big "duh" to me!
Sometimes I have a vision of the designers standing around laughing, "That should really puzzle the fans seventy years from now!"
Shane's right; they were sand hatches, and I believe the 'logic' was that the location would be familiar to people used to filling sand domes on steam power.
I think other builders, from early on, used separate 'sand pockets' near the respective trucks, accessed through panels near the running boards. Ed will have pictures.
Presumably by the era of the S8/S12 there were enough low-level sanding hoses or whatever available in yards...
on the VO series, they are sand hatches. The S series had the same car body but the sand hatches are not there on the S series. the difference between the two is internal engine changes. requiring the boxes to be moved. The only good pics I found were in the book Deisel builders Baldwin volume. Just as a funny note. in that book is an advertisement for The S series 1000hp version for $40000 dollars.
Shane
A pessimist sees a dark tunnel
An optimist sees the light at the end of the tunnel
A realist sees a frieght train
An engineer sees three idiots standing on the tracks stairing blankly in space
"One difference between pessimists and optimists is that while pessimists are more often right, optimists have far more fun."
I have a real affinity for the Stewart/Bowser models of the Baldwin switchers and have five different models. Does anyone know what the function of the two round structures at the rear of the hood on the VO660 model might be? I cannot find a photo showing the top of the hood of the prototype but the Stewart molds seem very accurate and I assume some VO's had these.