Some tankcars have short walk ways around the top dome and some run the cars length.Whats the difference ?For different loads?
The walkways are there for people to move around on the car, as necessary.
Some cars have only a walkway around the dome, and a ladder(s) to get up.
Some cars have more than one dome, and then they interconnect the walkways.
Some cars have a ladder on the end, so the walkway runs from the ladder(s) to the dome(s).
Before there were these platforms, with railings, there was just a ladder(s) to climb up to a “plank” to stand on, while you worked on the dome. It appears actual platforms started being used on chemical tank cars. Now I believe all tank cars have such platforms.
Ed
When I was young, it was explained to me that some loads required a worker to open the top of the car to verify it unloaded properly, clean the tank, or adjust valves/fittings on the dome. These cars would be more likely to have a walkway around the dome.
On cars that hauled simple loads like crude oil, where a pipe was attached to the bottom of the car to unload it, and it would not need to be cleaned because the next load would be the same commodity… these cars would be less likely to have a walkway because there was less need to access the dome.
Hopefully someone more knowledgeable can verify if this actually was the case.
-Kevin
General American Transportation Corporation, the parent of General American Tank Car or most commonly GATX, refers to the platform on top of most tank cars as the “top operating platfrom”, used to access valves, and connections used in loading and unloading the car. The manway for entering the tank is also accessed from this platform. On most smaller diameter tanks, the attachment of the access ladder to the side of the tank, is not a clearance problem, especially on older cars.
The length of the platform has been extended to move the opening in the handrails away from the operating area, for worker safety. Recent developements have seen additional crossbars added to the handrails to the effect the platform has become a “safety cage” to prevent workers falling off of cars.
Some cars have walkways the length of the car with the ladders on the ends of the car, for clearance reasons. The Association of American Railroads has a series of “plates” with dimensions cars must fall within, the most common of which is “plate C”. Plate C cars are almost universally acceptable on most railroads. Most clearance issues arise at the shippers and receivers. Many plants have close clearances, especially on curves. Since railroads bill for shipment based on the weight of each car, shippers found it would be cheaper to eliminate so many cars by packing more into each car. This caused the barrel of the car to swell, giving rise to clearance problems. To take full advantage of plate c, and eliminate conflict with side ladders normally found on tankcars, the ladders were moved to the ends of the car.
Since the first “pregnant whales” of the 1960s, shippers have found ways to get maximum capacity out of a tank of given length. When corn syrup tankers grew from the 16,000 gallon range to over 19,000 gallon
Thanks to all for the great information