Icing reefers

[ndbprr]

They were also high priority with precedence over most other freight running at or near passenger speeds.

[rcdrye]

Just to add a counterintuitive note:  Some refrigerator cars had bunkers that were set up to carry charcoal heaters to prevent produce from freezing in the winter.  There were also about 50,000 ventilated boxcars in service at one time for produce that just needed to be kept at the normal outside temperature.

[Scottish enthusiast]

Many thanks for this very helpful reply. As someone with a science/engineering background, I can fully appreciate the physics of the situation and how crushed ice would cool more than chunk would. What I hadn't appreciated previously was that :

a) meat needed to be kept more or less frozen whereas produce only needed to be chilled (It's obvious really when you think about it!)

b) two different grades of ice (crushed and chunk) were available at the icing stations.

Reefers of the North American kind were something we didn't really have here in the UK. I suppose it was because of the much smaller distances involved. We didn't have really long hauls like from the West Coast to the Midwest or East Coast here on this small island.

[rcdrye]

"Can anyone explain to this ignorant foreigner who's only become acquainted with North American railroads during the last ten years why a meat reefer is receiving crushed ice while produce cars are getting chunk ice?"

An excellent technical question.  Reefers set up for produce were expected to keep the produce cool, but not near freezing. The use of chunk ice kept them from getting too cold because the surface area of the ice chunk was relatively small compared to its volume.  Crushed ice got things colder, but needed to be replenished more often.

The development of mechanical refrigerator cars in the 1950s and 1960s swept away the icing platforms even before most produce and meat shipping moved to trucks.  There were still pockets where iced reefers were used into the early 1970s. 

[Scottish enthusiast]

Today's (Feb 23) Photo of the Day shows reefers being iced. Can anyone explain to this ignorant foreigner who's only become acquainted with North American railroads during the last ten years why a meat reefer is receiving crushed ice while produce cars are getting chunk ice?