Plug Door Boxcars (was "Hobos")

The old metal lanterns make a good persuader", too! Hit one upside the head with a lantern, he's gonna see stars!

Gadfly

Enough with the talk of hobos. Please.

What makes a plug door so different from a slider. Is it because the door is "drawn in" as it is closed to seal the contents from the weather or theft? Why is an unsecured door a hazard, a few postings mention the doors falling off or fouling the ROW if open. Do the doors swing out if loose?

Thanks!

toolmaker wrote:What makes a plug door so different from a slider. Is it because the door is "drawn in" as it is closed to seal the contents from the weather or theft? Why is an unsecured door a hazard, a few postings mention the doors falling off or fouling the ROW if open. Do the doors swing out if loose?

Thanks!

A plug door is MUCH thicker then a standard sliding door because of the design. It has extra bracing and is made of thicker steel to be strong enough and ridgid enough to seal such a large opening under pressure. The added thickness as well as all the associated hardware such as locking arms, gears and housing for the spinner also add to the weight. The shear weight of the doors mean that if enough inertia were created, the door can rip itself off the hinges. If it were to fall off, it could obviously injure or kill someone. When a plug door is opened, it sticks out from car so that it can slide open and be clear of the side of the car. Because of how far it sticks out, it can be a hazard to station platforms and other close clearence areas. Modern track centers will allow a train with an open plug door to pass another train safely, but there is not much more room then that. If two trains passed and each had an open plug door open, they could hit.

When a plug door is opened via the spinner. It pops out from the car and slides on a set of rails on the top and bottom of the car. It does not swing out. Both a top and bottom bracket would have to break before that happened.

I am glad the topic is unlocked again. I have a better understanding of what’s involved to operate these doors. To see what “spinners” are. I did a search and discovered a manufacturer’s video showing how to open and close plug doors.

http://www.arnoldcompany.com/plug_door_ ... opener.htm.

And found this safety advisory on the CP website: AAR Safety Advisory - Opening Boxcar Plug Doors

https://www8.cpr.ca/cms/English/Custome ... +Doors.htm

Do these plug doors have a pressure difference like the plug doors on aircraft?

Passenger wrote:Do these plug doors have a pressure difference like the plug doors on aircraft?

Uh, no. Boxcars are not pressurized.

Actually, I think there is one case where boxcars using plug doors ARE pressurized, though minimally: Cryogenic reefers. I'm not overly familiar with loading operations, but I believe liquid CO2 is pumped into the car after closing the doors. I understand these cars have fallen out of favor vs. mechanical reefers as one too many unloaders were asphyxiated upon entering a car that wasn't purged. Unfortunately, the same thing occasionally happens when workers go inside tank cars and tank trucks to clean or repair a tank that was prior purged with nitrogen and not subsequently ventilated.

Cowford wrote:Actually, I think there is one case where boxcars using plug doors ARE pressurized, though minimally: Cryogenic reefers. I'm not overly familiar with loading operations, but I believe liquid CO2 is pumped into the car after closing the doors. I understand these cars have fallen out of favor vs. mechanical reefers as one too many unloaders were asphyxiated upon entering a car that wasn't purged. Unfortunately, the same thing occasionally happens when workers go inside tank cars and tank trucks to clean or repair a tank that was prior purged with nitrogen and not subsequently ventilated.

The cryo cars are not pressurized. They are simply filled with Co2 to cool them. But they operate at 0psi. They are not rated as pressure vessels. The door seals would not handle any pressure.

NV290 wrote:

Cowford wrote:Actually, I think there is one case where boxcars using plug doors ARE pressurized, though minimally: Cryogenic reefers. I'm not overly familiar with loading operations, but I believe liquid CO2 is pumped into the car after closing the doors. I understand these cars have fallen out of favor vs. mechanical reefers as one too many unloaders were asphyxiated upon entering a car that wasn't purged. Unfortunately, the same thing occasionally happens when workers go inside tank cars and tank trucks to clean or repair a tank that was prior purged with nitrogen and not subsequently ventilated.

The cryo cars are not pressurized. They are simply filled with Co2 to cool them. But they operate at 0psi. They are not rated as pressure vessels. The door seals would not handle any pressure.

It would be hard to say it works at 0 psi. The process is thus, liquid CO² is pressurized, and sent into a compartment at the top of the car, this creates CO² snow. The food product is then loaded into the car, and doors closed. As the snow sublimates, it returns to a gas form. When it returns to gas form, it expands.

All the Cryo-Trans cars were converted to mechanical reefers.

HoggerKen wrote: It would be hard to say it works at 0 psi. The process is thus, liquid CO² is pressurized, and sent into a compartment at the top of the car, this creates CO² snow. The food product is then loaded into the car, and doors closed. As the snow sublimates, it returns to a gas form. When it returns to gas form, it expands. .

But the car is not sealed. So excess pressure is vented. Therefore it never operates under pressure. This was an issue early on as people were afraid that if somebody were attempt to open the door that it could injure someone if pressure inside blew it outward. So the cars have pressure vents that do not allow any pressure to develop.

HoggerKen wrote: All the Cryo-Trans cars were converted to mechanical reefers.

Not so. I see Cryotrans cars almost daily that are still working off of Co2. And very often they are simply used as insulated plug door cars with no cooling at all. But they are 100% intact with all valves, fitting and fill ports. We get beer cars 5 times a week that are CryoTrans cars.

Thanks NV290, I stand corrected.

NV290 wrote:

HoggerKen wrote: It would be hard to say it works at 0 psi. The process is thus, liquid CO² is pressurized, and sent into a compartment at the top of the car, this creates CO² snow. The food product is then loaded into the car, and doors closed. As the snow sublimates, it returns to a gas form. When it returns to gas form, it expands. .

But the car is not sealed. So excess pressure is vented. Therefore it never operates under pressure. This was an issue early on as people were afraid that if somebody were attempt to open the door that it could injure someone if pressure inside blew it outward. So the cars have pressure vents that do not allow any pressure to develop.

HoggerKen wrote: All the Cryo-Trans cars were converted to mechanical reefers.

Not so. I see Cryotrans cars almost daily that are still working off of Co2. And very often they are simply used as insulated plug door cars with no cooling at all. But they are 100% intact with all valves, fitting and fill ports. We get beer cars 5 times a week that are CryoTrans cars.

From: http://www.mhwgroup.com/Cryo-Trans.htm

In 2000, CTI had begun the conversation of their CO2 refrigerated fleet to 64’ mechanically refrigerated railcars with state-of-the-art refrigeration systems and two-way Global Positioning Systems (GPS).

In 2003, CTI produced its first run of 100 new 72' interior length mechanically refrigerated railcars.

In the Fall of 2005, CTI ordered 429 additional 72' interior length mechanically refrigerated railcars for 2006 delivery.

I don't see any non mechanical CRYX cars hauling wine these days. I do see system boxes doing the honors. Canandaigua, working through Hub Group for example did use the older CRYX cars prior to being refitted to mechanical as reported in 2003 by Logistics Today. Hub used the UP/CSX "Wine Connection" (since folded under the "Express Lane" umbrella).

Beer is a different story. Last I looked in 2007, they were using any cars they could get their hands on. If older CRYX cars are being used, the CO² systems are disabled. Since the CRYX CO² cars were developed for frozen foods, and there was no control over the temperatures, GPS, and door alarm, they became inflexible as other commodities and demand increased. This was due to customer demand.

HoggerKen wrote:If older CRYX cars are being used, the CO² systems are disabled.

That may very well be. All i can tell you is the cars still have the associated piping, valves and labeling for the Co2 system and no mechanical refrigeration of any kind.

More then likley, they are simply using older cars not yet converted to mechanical as nothing more then an insulated plug door car.