Placards do not indicate what a car is "capable" of carrying, they indicate the hazard that actually exists. If there is an incident, they tell first responders "this is what is in this car".
This is correct. The placard really belongs to the load, not the car. First responders certify (here it's every 3 years) on responding to incidents involving hazardous materials. Part of that training includes placards. We all carried a book with the codes that are on the placards so we could tell what the cargo was from a distance. Procedure as taught was to stand off from an incident involving certain types of vehicles (tank cars were on the top of the list) and read the code on the placard through binoculars and only approach the wreak after you determined it was safe. I spent 9 hours directing traffic one night after a CN train derailed and the interstate was shut down because of what was in some of the derailed cars. It was later determined that none of the cars were leaking, but it was a major incident for couple days.
Placards are an important detail.
Thank you for this thorough explanation. I appreciate the greater fidelity.
I don't care what many Americans say about Canucks, or how close we came to conquering Quebec in 1775!
1. Always current.
2. While certain tank car designs might be suitable for different commodities, any given tank car can't just switch around as the first load will leave traces that would contaminate the second.
So no, no multiple placards unless its a multi-compartment car that can actually carry different commodities in different sections, and as in your example, an LPG car cannot be reloaded with AA without being fully cleaned out at a tank car maintenance facility. (And placards are not removed unless a car is cleaned either, because of the trace amounts that will remain behind...)
Chris van der Heide
My Algoma Central Railway Modeling Blog
1. Placards would be current to the era, not the build date of the car.
2. If a car was being used to haul various commodities vs captive service with a single commodity, then the placards must be changed to reflect what is being hauled.
Mike
When I was working, placards were applied specifically for that one particular movement. When the car was made empty, the placards were removed and a "dangerous empty" placard was applied if required. The customer was responsible for affixing the proper placards each time the car was released.
Charlie
Perhaps these questions belong in this forum. I am curious about the answers:
Two questions:
1. Would tank cars need to get their placards updated to reflect updated regulations? In other words, if you have a 1960s tank car on a 1980s layout, what placards to use--based on the build date or updated ones to reflect time period being modeled?
2. Given that certain types of tank cars carry different products (e.g. 33K cars transport LPG and AA), can they have multiple placards affixed to a car or do the placards change based on what a car is currently carrying?