I am looking to model a piggy back trailer loading/unloading facility about the 1940’s. i am wondering how they loaded the train. Did they back each trailer down the train or was there another way they did it. Any of the pictures that I have seen do not show much, mainly the ramp at the end of the train. Nice pictures but not a lot of infromation.
Thanks
Rick
In some cases, the trucks were driven onto the flat car and the trailer dropped. In others, an overhead crane lifted the trailer and put it onto the flat car. Other types of crane were also used. Most or all of these methods are still used.
One I’ve seen still in use is at the military base near my home. A line of flat cars are put onto a spur. At the end of the spur is a ramp that meets with the end of the car. The vehicles to be loaded are driven up the ramp, onto the first car and right down the line until they get to the farthest empty flat car.
Piggy back operation in the 40’s would be been ‘circus’ style loading/unloading, and a lot of ‘tie down’ straps. 5th wheel hitches were not in use yet on railroad equipment. Not too many railroads were using TOFC equipment at the time. The North Shore, and CGW come to mind as early operators of TOFC…
Jim
“Circus” style was the method of loading trailers on flats in the 1940’s. Overhead cranes were not used much, if at all, at that time since the trailers were not reinforced enough to be picked up by a crane.
Circus-style loading means loading a string of flats up a ramp at the end of the string. Trailers were backed up the ramp and down the string of flats to the first available position. Trailers were set down on their dolly wheels and multiple chains were attached at 4 or 5 locations to secure the trailer to the flat. As Jim mentioned, 5th wheel hitches were not in use at the time. The tractor had to drive off the same way it came on, so loading was often a fairly long process and somewhat labor-intensive with all those chain hold downs.
In the 1950’s and 1960’s, collapsible 5th wheels were installed on flat cars and chains were eliminated since it was determined that the 5th wheel hitches could hold the trailer in place. Trailers were still end-loaded. The tractor driver rarely left his tractor. As he dropped the trailer, another man would raise the hitch to engage the pin on the trailer and secure it.
Definitely by the 1960’s, hydraulic-lift 5th wheels were used on the tractors and hydraulic-lift or spring-loaded hitches were in use on the flats. The driver could hook up to a trailer in the yard, hydraulically lift it without having to raise the dolly wheels, drive to the ramp, back up the ramp and down the string of flats. As the trailer passed over the hitch, a release mechanism would allow the hitch to swing up. The driver then lowered the trailer onto the hitch and rocked the trailer to engage the pin in the hitch. The hitches on the flats were taller than the dolly wheels on the trailer so the dolly wheels never had to be moved. Only one man was needed to load a string of flats. Often, there were multiple ramps being loaded at one time, depending on destination.
Unloading was accomplished in reverse order. As the tractor driver hooked up
Don’t forget in the forties, trailers were single axled and about 26 feet in length, more or less. and flats were 40 or 50 footers, with side rails.
[quote]
QUOTE: Originally posted by dgwinup
“Circus” style was the method of loading trailers on flats in the 1940’s. Overhead cranes were not used much, if at all, at that time since the trailers were not reinforced enough to be picked up by a crane.
Circus-style loading means loading a string of flats up a ramp at the end of the string. Trailers were backed up the ramp and down the string of flats to the first available position. Trailers were set down on their dolly wheels and multiple chains were attached at 4 or 5 locations to secure the trailer to the flat. As Jim mentioned, 5th wheel hitches were not in use at the time. The tractor had to drive off the same way it came on, so loading was often a fairly long process and somewhat labor-intensive with all those chain hold downs.
In the 1950’s and 1960’s, collapsible 5th wheels were installed on flat cars and chains were eliminated since it was determined that the 5th wheel hitches could hold the trailer in place. Trailers were still end-loaded. The tractor driver rarely left his tractor. As he dropped the trailer, another man would raise the hitch to engage the pin on the trailer and secure it.
Definitely by the 1960’s, hydraulic-lift 5th wheels were used on the tractors and hydraulic-lift or spring-loaded hitches were in use on the flats. The driver could hook up to a trailer in the yard, hydraulically lift it without having to raise the dolly wheels, drive to the ramp, back up the ramp and down the string of flats. As the trailer passed over the hitch, a release mechanism would allow the hitch to swing up. The driver then lowered the trailer onto the hitch and rocked the trailer to engage the pin in the hitch. The hitches on the flats were taller than the dolly wheels on the trailer so the dolly wheels never had to be moved. Only one man was needed to load a string of flats. Often, there were multiple ramps being loaded at one time, depending on destination.
Unloading was ac
you should try to find kalmbach book on intermodal operations. gives a history of intermodal and how to model an intermodal facility etc.
tom