Building refrigerated trailers for rail service
Sep 1, 2005 12:00 PM
If carriers decide to use rail service for additional capacity, they need to know how to select trailers that can withstand the stresses of rail travel. To provide that information, the Refrigerated Division of the Truckload Carriers Association assembled representatives from two trailer manufacturers and the two primary North American manufacturers of refrigeration units to detail the special requirements for rail service equipment.
From the trailer industry, the panel included Craig Bennett, senior vice-president sales and marketing for Utility Trailer Manufacturing Company; and Richard Giromini, executive vice-president and chief operating officer for Wabash National Corporation. Refrigeration system representatives were Scott Spaulding, director of sales, national accounts at Carrier Transicold and Jerry Duppler, national account manager — rail for Thermo King. The Refrigerated Division annual meeting took place in Dana Point, California, July 13 to 15, 2005.
The Association of American Railroads publishes two standards for intermodal equipment. The more restrictive of those two standards, M931, applies to trailers intended for almost full-time rail use, Bennett said. However, the railroads are not enforcing those requirements as strictly as they did 15 to 20 years ago.
The M9931 standard is a more relaxed set of specifications tailored for the occasional rail user, Giromini said. Standards aside, truckload carriers need to be concerned about several things when ordering trailers that will be used in intermodal service from time to time. Air suspensions need to be upgraded. Realize, he said, that when a trailer is lifted, the air springs will deflate. When that trailer is put down on the rail car, the potential exists for the air bags to get pinched as they collapse under the renewed load. One way to prevent this is to put stops in the air bag system, Giromini said.
Top and bottom rail protection
Lift pads are needed, obviously, as are protectors for the upper side rail, Giromini said. “The AAR standards recommend that all accessories be recessed at least six inches from the surface of trailers,” he said, “but we suggest recessing them a full eight inches to provide complete clearance from the lift arms on the rail handling equipment. The trailer kingpin is the most critical item. It must be rated to match and must be certified to meet the restrictive limits required by AAR M931 regardless of whether the trailer will be in full-time rail service or only placed on the rails occasionally. The upper coupler protection plate should cover the entire nose section of the trailer to prevent the rail car stanchion from damaging air and electrical lines if it is not engaged properly.”
Conventional highway refrigeration units work fine in rail applications, Spaulding said. They are designed to handle the stresses of highway use as well as rail. Intermodal users need to focus on the things about rail applications that are different from highway use. The biggest difference is that trailers are handled differently in a rail yard. Highway trailers don't commonly get picked up by cranes. In addition, handling in a rail yard is done in extremely close proximity to other trailers and equipment.
Cranes and the potential for bumping into lift arms or other trailers leads directly to the need for protective bumpers around the units, Spaulding said. If trailers are used primarily in intermodal service, bumpers are a necessity. If intermodal is only an occasional application, the cost and weight of bumpers need to be balanced against the potential for damage. It's possible to add up to 200 lb with a full intermodal protection package, he said.
Once a trailer leaves the yard, it is on its own — no driver to monitor operation, Spaulding said. That suggests equipping trailers with remote monitoring devices. At the least, it indicates that fleets should make full use of the recording devices built into the refrigeration unit to provide information during inspections and preventive maintenance. On the rails, a refrigeration unit that quits doesn't have a driver to restart it, he said. To protect the load, rail refrigeration units should automatically attempt to restart if they quit running. “If a refrigeration unit shuts down in route, the train is going to continue down the track,” Spaulding said. “No one is going to go back down the train and attempt to start the unit.”
On the highway, a driver can check reefer fuel during other routine stops. In intermodal use, carriers need to plan for the unit to run for the entire trip with only the fuel on board when it began, Spaulding said. Carriers need to know the transit time and be prepared to provide enough fuel to cover that distance and to have some cushion in case of delays. “In rail applications, fuel supply is critical; the unit simply cannot be allowed to run out of fuel,” he said.
The long rail lanes are from the West Coast to Chicago, Duppler said. Carriers need to plan for 72 to 96 hours of unattended refrigeration unit operation. One of the good things that has been developed in the past five years is remote monitoring that tracks unit operation and alerts station personnel to attend to a unit immediately upon arrival if needed, he said.
300 to 600 lb extra
The extra weight required for rail operation covers a wide range, Bennett said. If a trailer is equipped with aluminum lift pads instead of steel pads, the addition can be as little as 100 lb up to 1,500 to 2,000 lb for a full rail package. Almost no fleets are specifying a full rail protection package any more, he said. The actual weight increase for rail specifications usually ranges from 300 lb to 600 lb.
The basic refrigeration unit for rail applications is the same as that used over the road, so the price is the same, Duppler said. The price differences for rail application come from optional equipment such as larger fuel tanks, which can add $300 to $400 to the basic price. Bumpers and other protection packages vary widely in price depending on design, he said. In general, carriers can add a rail protection package to a refrigeration unit for $300 to $700. The big price jump for rail application is the remote monitoring system, which can add $1,500 to unit purchases.
Bumpers and other unit protection devices probably cost between $500 and $600, Spaulding said. Other costs factors include custom programming for unit control systems, if desired. One change that Carrier Transicold recommends is an upgrade to the unit fuel filtration system, he said.
Full compliance for $1,200
Price increases depend entirely on what a fleet wants to do, Giromini said. The minimum level rail package can probably be purchased for as little as $300. Full compliance with M931 will probably boost the price for a trailer by $1,200. “Wabash National fully recommends bumpers around refrigeration units, because the units will get bumped,” he said. “It doesn't matter if the trailer is used in rail applications constantly or just once a year; eventually, something will hit the refrigeration unit.”
Utility Trailer is hearing more requests for rail equipment, Bennett said. In addition to building new trailers for intermodal use, the company is getting a lot of questions about retrofitting existing trailers, he aid. “At the same time we hear requests for intermodal equipment, we hear that fleets do not want to add tare weight to their equipment,” Bennett said.
“We see a growing level of interest in intermodal applications,” Giromini said. “However, converting that interest into trailer orders has proved to be quite a different matter.”
Carrier Transicold hears increased interest in intermodal equipment, but it still comprises an extremely small percentage, less than 5%, of the units the company ships, Spaulding said. “If we add the units provided for box cars, the percentage may go up to 10% of the number of units shipped,” he said. “We see a positive trend for equipment delivered to dedicated intermodal fleets. What we have been unable to quantify is how many highway fleets are putting their trailers into periodic rail service.”
Recording devices provide two positive benefits, Spaulding said. First, having unit operating and temperature data can be invaluable in helping carriers defend against freight claims. “Second, the data from those recorders helps Carrier Transicold design a more reliable unit for rail use,” he said.
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