As I have begun operations on my layout, many things are occuring to me that I never would have thought of otherwise. Most of my reefers are ice cooled but I do have several mechanical reefers and one of the industries they serve is a cold storage warehouse.
At the risk of displaying my ignorance, I am guessing that mechanical reefer are dependent on the car being in motion to generate the cooling mechanisms. If that is the case, wouldn’t there be some urgency in getting these cars to their destinations ASAP rather than allow them to sit for any significant time in a yard. Both the ice cooled and mechanical reefers are insulated and have plug doors, but a stationary ice reefer will continue to cool as long as there remains ice in the bunkers. How long could a mechanical reefer remain staitonary and continue to keep its contents properly refrigerated?
This became an issue during my latest opreating session when a train dropped a couple mechanical reefers in my main yard, but they couldn’t be delivered immediately to the cold storage facility because there were a couple of ice cooled reefers at the dock that had been delivered earlier in the session.
While some icers had fans that were mechanically driven when the car was in motion, the term mechanical reefer to me always meant one that had a self-contained refrigeration plant, ususally driven by a diesel engine.
These cars needed no ice since they worked just like your home freezer although the were diesel powered and not electrical. Aside from them not needing ice, these cars can easily maintain a much lower temperature that regular ice cooled reefers. -10 deg. suitable for frozen foods.
Only restrictions I can remember for their movement was they were not to be placed next to placarded cars (flammable-explosives-etc)
Charlie is correct. There is no urgency to keep the car in motion. The reefer unit runs on diesel, so the limit for it is the size of the fuel tank. I don’t recall exact sizes, but it’s sufficient to cross the country and then wait at the far end for a suitable buyer, in some cases. Produce is often shipped and then sold in transit or at the final destination, so some delays in unloading are possible.
If you aren’t sure of the answer, the best thing to do is ask the question.
In regards to the the refrigerated cars having to be in motion, the ice cooled reefers are the cars that benefited the most from being in motion. Some of those cars had a mechanically driven fan to circulate the inside air to keep a more consistant temperature thoughout the carload. Other times the ice hatches could be left open depending on what the car was hauling. These methods improved on the simple thermo-dynamic circulation created by heat convection: hot air rises and is replaced by cold air which is replaced by the hot air which is cooled by the ice within this closed car.
The mechanical reefer utilised a diesel engine to run a refrigeration system similar to what is used on highway trailers. This system would cool and circulate the air inside. These cars did not require car motion to circulate the cold air and reduced the costs involved with icing the cars.
Looks like refueling from a tanker truck is common - but I haven’t been able to find out what companies like Railex which run unit train mech reefers to their huge warehouses (like the one in Rotterdam, NY).
Probably tank trucks as well, but…
ETA. Now you got me wondering, and while I still haven’t found it, I did find this interesting little slide show about the Railex Mech Reefer operations which shows modern era cold storage warehouse operations, among other things.
In the past, refueling tended more twoards fixed points. But as the new kid on the block comapred to ice, there often wasn’t a lot invested in fixed facilities in many locations, so there always seem to have been fuel contractors sent to handle this.
Now, because trucks are so flexible, that’s probably the dominant mode of refueling. Plus fixed facilities require significant investment for enviro reasons, so these tend to be only at very large terminals.
I suspect (assume) that most cars return empty. In that light they may go back with the cars shut off and be refueled at a home yard or location. To refuel all over the country would be a nightmare.
PRR Ran a “hot reefer” train that had priority over everything except a passenger train.This train rated the best locomotives so it could maintain its tight schudele-even PRR’s TTX trains had to whoa up and wait on this train…I know 80% was PFE and the last 20% was a mixture of Santa Fe and FGX…IIRC it ran between St.Louis and its final distention was either in NY or NJ.Even
Larry, what years was that train in operation? Must have been before my time to warrant a dedicated train. I would guess it was an Enola train unless there was enough New York City traffic to make a complete train back then.
Another point; I doubt if mechanical reefers saw a lot of fresh produce or fresh meat loads since they were able to keep much lower temps and therefore were used more for frozen foods. At least, that was the case when i was working.
Charlie is right, keep in mind these refridgerators, either with ice bunker or mechanical, were not always used for frozen cargo. The hatches could be positioned on ones with ice bunkers to try and meet a preffererd temperature range with air circulating to keep some items from freezing. For example apples, etc. Mechanical reefers are nice in that you can control the temperature more easily.
Don’t overlook the RB and RBl insulated box cars as these could be loaded and moved with very little temperature change to the load regardless of the weather outside because of their insulation. ‘RB’ is refriderator bunkerless, the ‘l’ would indicate load dividers. Chris
Charlie,The first time I saw that train it was pulled by a J1 and later brand new GP9s and RS11s replace the Js,M1s and L1s that usually assigned to this train probably around 56.This reefer train ran until the mid 60s.The 60 era train was a mixture of 50’ mechanical reefers and 40’ ice reefers.GP30s,35s and U25Bs had the honors during this time.
I know it came through Logansport,Bradford and into Columbus on the Piqua Line btween 6:30 pm-7;00pm-that was right after PRR passenger train and C&O’s Sportsman left the Union Staion…
OK, I learned something here. I had always guessed that the generators on the mechanical reefers were powered by the movement of the car. I didn’t realize they had their own on board diesel generators. I guess my next question would be how long could they operate without refueling. I model summertime so my reefers would have to deal with maximum high temperatures.
In the days of the ice-cooled reefers, they could also be used as ventilated cars, with or without ice, and as insulated cars, with no ice. In winter, many were equipped with charcoal or propane heaters, either placed in the bunkers or permanently installed beneath the car, making them useful for loads which needed to be protected from freezing. This could apply to produce, of course, or non-perishable stuff such as paint. Unless a car is in dedicated service, backhaul movements might carry any clean cargo suitable for such a car.
I’m not sure, but I seem to recall reading that mechanical reefers are also capable of heating for lading which requires it.
Well, another good question, and until someone with better info comes along, the best I could find was 21st century refrigerator units for trucks or railcars use anywhere from 0.6 to 1 gal per hour of diesel fuel under full load. AFAIK, the new reefers have a 500gal fuel tank, so that would be over 500 hours of operation under load.
I leave the exercise up to the reader to find out how much fuel those old-school 1970s era Trane refrigerator units used under full load.
Mechanical reefers are powered by small diesel engines.The newer cars and some older rebuilt cars have the same kind of reefer units used on highway and delivery trucks.At the industrial park where I work,there are a couple of places that recieve produce from the west coast and can get 1 to 7 cars at a time.I have seen a local oil companies tank trucks putting fuel in the cars several times.
there are a lot of freight that can be loaded in empty reefers for the return trip.Almost anything that goes in a boxcar can go in a reefer though they try to keep it to food items.
The diesel units do not just cool to up to -20,but can heat to+80.Some of the new units are hooked to a satilite system where all systems and functions can be watched and even adjusted while in transit.
Having pulled many Reefer Trailers and also working for Orval Kent Food Co. out of Wheeling IL. over the road. The onboard reefer units had 60 gal tanks, at consuption of 1gal an hour at constant run. The new Transcold Reefers, would start and stop, on ther’e own, thereby conserving fuel. Also having worked at CSX Intermodel with many reefers,40ft containers, on a five pack, tub car, there would be 8 40ft reefers double stacked at the coupler ends to the middle well, where there would be, two 20ft Diesel gensets that supplied electric power to run the reefer units, while on the stack train. The only time you will see a diesel trailer reefer running on a ‘‘Pig’’ if its alone and will have to be refueled in transit, with crew changes. Also when the 40 ft containers would be unloaded, a crew would have to come and unhook the cables and then start the diesels, before the containers would even be unloaded. All big facility Intermodal yards had on premices contractors whose only job, was taking care of reefers. CSX’s contractor was on site 24/7.
A long time ago in teh MR Symposium on Electronics, they gave a design for a mech reefer sound module. It was basically a buzz sound. Last year, some company (don’t remember which) was selling a mech reefer with onboard sound. I have a few mech reefers. Does anyone know of there is a sound module availabe for a mechanical reefer engine sound?