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Preparing for extreme cold weather operations

By Christopher W. Ferrone

On January 16 the ambient temperature in Chicago reached minus 24 F with the associated wind chill in excess of minus 40 F. On that day, the North Pole registered minus 8 F. The temperature was so extreme that no matter how anyone dressed, the average person could only stay outside for about 15 minutes. All I could think about was the scene from Ice Station Zebra where the submarine came up vertically through the ice. I was looking for the submarine to appear in Lake Michigan.

Needless to say this type of weather warrants extraordinary preparation of a motorcoach fleet, the people servicing them and the logistics to control the process.

But even with the most diligent preparations, temperatures this extreme still create problems for motorcoaches. In temperatures this low, the typical motorcoach does not have enough insulation to keep the interior of the coach warm during a road failure. Not only the comfort, but the safety of passengers depends on diligent preparation before the winter season.

One common misconception is that the wind chill factor worsens the affect on a vehicle. That may be true for the technicians working on the coach, but the truth is wind chill does not detrimentally affect a part or component already at the ambient temperature.

As necessary and important as it is to prepare properly and methodically, preparation would not have solved every problem we experienced during this extraordinarily cold snap. After fully preparing our fleet at Chicago Sightseeing, we were operating at a 90-percent readiness ratio. Mechanically, the most common problems are the inability to release the parking brakes and the failure of the suspension system

Timing is key to successful cold weather preparation. Allow enough lead time before the cold weather sets in to carry out the preparation. We begin in October to ready the Chicago Sightseeing fleet, which gives us enough time to source the necessary parts and supplies to complete the task.

The operator who falls behind and then tries to catch up when cold weather sets in may have a slew of motorcoaches that do not operate successfully.

Motorcoach preparation

These are the steps operators must plan, coordinate and execute to prepare for extremely cold weather conditions.

  • Rebuild the air dryer and the air dryer purge valve.
  • Confirm the air dryer heating element has power and ground, and the element is heating the base of the dryer assembly.
  • Insulate the air dyer inlet and outlet with foam pipe insulation purchased at any hardware store.
  • Change the suspension filters and fittings located on the wet tank and the accessory tank.
  • Change the Puraguard spin-on filter at the air dyer.
  • Change or confirm the correct cut-in/cut-out air pressure setting of the air compressor governor.
  • Confirm that the air dryer purges at the proper air pressure level.
  • Repair all air leaks in the entire motorcoach air system. A motorcoach with air leaks will usually freeze faster than one with no air leaks. This is due to the fact that when air leaks are present, the air compressor cannot keep up with the leaks and therefore never reaches the cut-out pressure, which in turn prevents the purging of the air dryer expelling the accumulated water.
  • Change the parking brake diaphragms.
  • Check/replace the batteries, confirm the condition of all battery cables and connections.
  • Outfit the emergency parking brake fill port with a quick connect air hose fitting and manual twist valve. This will assist in boosting air into the frozen bus’s parking brake tank.
  • Drain all air tanks daily.
  • There may be a drain-daily fitting at the oil collection system. After draining the pull ring style drains, remember to rotate them at least 180 degrees in order to clear out the ice that has formed during the draining and any road debris that is on the valve stem. The ice and debris will prevent the valve stem from seating and a constant air leak will remain at the valve in question. The mechanic should place his bare hand over the front of the valve confirming that no air is leaking from the valve.
  • In some instances on older motorcoaches it may be necessary to replace the air tank drain pull-ring valves at the beginning of the preparation process.
  • After draining the air tanks, apply WD-40 or similar product to the exposed rubber diaphragms of the quick release valves for parking and service brakes, ABS solenoid valves, service brake relay valve, inversion valve and the exterior of the leveling valves. This will prevent the accumulation of ice on the base of the valves.
  • When the temperatures drop, confirm the motorcoach has a full tank of diesel and that all lubrications have been checked and filled, and that the radiator and surge tanks having been properly treated with anti-freeze coolant.
  • To prevent fuel gelling, change all fuel filters and add anti-gel additive to the fuel tank for each full tank of diesel.
  • Follow much of the same procedures for the service truck. Even though it is not a revenue vehicle, cold weather preparation is just as vital for when the call comes for a road rescue.

In addition to preparing the motorcoaches for sub-zero temperatures, the personnel staff must also be in good operating order. Road mechanics should wear protective clothing, which includes a facemask, insulated overalls, a waterproof coat and gloves that extend above the wrist.

Rescue tools include a small hand-held torch that has the lighter mechanism on the tip,  and at least two spare tanks of gas. These are available at any hardware store or home center. A final piece of equipment for the frozen road rescue is a long, flexible, corrugated rubber tube, such as shop style exhaust pipes, used to thaw frozen a bus’s air system. Attach one end of the hose to the tailpipe of the rescue bus or service vehicle and extend the other end to the area around the air dryer. Rev the rescue vehicle engine RPM to 1200-1500 to heat the exhaust piped into the air dryer area. The flow of hot engine exhaust will thaw the air dryer and wet tank. The parking brake should then release and the coach can return to the garage.

  • Repair all air leaks in the entire motorcoach air system. A motorcoach with air leaks will usually freeze faster than one with no air leaks. This is due to the fact that when air leaks are present, the air compressor cannot keep up with the leaks and therefore never reaches the cut-out pressure, which in turn prevents the purging of the air dryer expelling the accumulated water.
  • Change the parking brake diaphragms.
  • Check/replace the batteries, confirm the condition of all battery cables and connections.
  • Outfit the emergency parking brake fill port with a quick connect air hose fitting and manual twist valve. This will assist in boosting air into the frozen bus’s parking brake tank.
  • Drain all air tanks daily.
  • There may be a drain-daily fitting at the oil collection system. After draining the pull ring style drains, remember to rotate them at least 180 degrees in order to clear out the ice that has formed during the draining and any road debris that is on the valve stem. The ice and debris will prevent the valve stem from seating and a constant air leak will remain at the valve in question. The mechanic should place his bare hand over the front of the valve confirming that no air is leaking from the valve.
  • In some instances on older motorcoaches it may be necessary to replace the air tank drain pull-ring valves at the beginning of the preparation process.
  • After draining the air tanks, apply WD-40 or similar product to the exposed rubber diaphragms of the quick release valves for parking and service brakes, ABS solenoid valves, service brake relay valve, inversion valve and the exterior of the leveling valves. This will prevent the accumulation of ice on the base of the valves.
  • When the temperatures drop, confirm the motorcoach has a full tank of diesel and that all lubrications have been checked and filled, and that the radiator and surge tanks having been properly treated with anti-freeze coolant.
  • To prevent fuel gelling, change all fuel filters and add anti-gel additive to the fuel tank for each full tank of diesel.
  • Follow much of the same procedures for the service truck. Even though it is not a revenue vehicle, cold weather preparation is just as vital for when the call comes for a road rescue.

In addition to preparing the motorcoaches for sub-zero temperatures, the personnel staff must also be in good operating order. Road mechanics should wear protective clothing, which includes a facemask, insulated overalls, a waterproof coat and gloves that extend above the wrist.

Rescue tools include a small hand-held torch that has the lighter mechanism on the tip,  and at least two spare tanks of gas. These are available at any hardware store or home center. A final piece of equipment for the frozen road rescue is a long, flexible, corrugated rubber tube, such as shop style exhaust pipes, used to thaw frozen a bus’s air system. Attach one end of the hose to the tailpipe of the rescue bus or service vehicle and extend the other end to the area around the air dryer. Rev the rescue vehicle engine RPM to 1200-1500 to heat the exhaust piped into the air dryer area. The flow of hot engine exhaust will thaw the air dryer and wet tank. The parking brake should then release and the coach can return to the garage.

Christopher W. Ferrone is  president of Americoach Systems, Inc., Glenview, IL, an  engineering firm specializing in transportation technology, analysis and engineering safety.

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Posted by on Mar 1 2009. Filed under Maintenance. You can follow any responses to this entry through the RSS 2.0. You can leave a response or trackback to this entry

1 Comment for “Preparing for extreme cold weather operations”

  1. I wish to say, nice webpage. Im not sure if it has been addressed, however when using Firefox I can never get your complete web page to load without refreshing alot of times. May just be my modem.

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