The Northern Pacific fitted up 28 prior fully refrigerated cars as half reefer/half dry lading (merchandise). Then in 1951 they converted another 25. The reason given on the 1951 AFE was "They have proven economical in the reduction of ice used and adaptability to the service requirements and it is recommended that 25 additional cars be fitted up." That is 53 cars and to me, that is notable. In 1953, they added more cars. So at least on my railroad, in my 1953 timeframe, LCL traffic is a going thing. I am working to get data and plans about these cars together and in a manner such as to recreate these cars as a model.
Add to this, that the Northern Pacific had the Northern Pacific Transport Co, serving as the last step to many companies dock for delivery. A name not unfamiliar to many on this list, Richard Yaremko has written in my historical societies rag about those operations should someone be moved to read about that further. In that, we here seem to suffer from a vision when trucks are mentioned - in a win/loose manner. Many of our railroads here had some sort of trucking operations or contractual agreements established (well prior to the end of this lists 1960 cut off) that served both the railroads interests and the shippers. And that helped keep LCL alive through this lists time frame.
Freight Forwarders are mentioned above. Here is an undiscovered, unwritten source of railroad traffic that is well in need of being noticed. I have researched on and off for years about this trying to get together a critical mass suitable to be presented at CCB or Chicagoland. Acme was one name and there were others. Often (on my road) they had floor space rented in the freight depot in larger locations. That is two industries in one building, and a chance for operationally more switching. Freight forwarder traffic was hot as railroad traffic and I have letters from high up tracking the movements of these cars and fiery telegrams when a car connection was missed. Instructions on manifesting train make up have freight forwarder cars in the top priority of four or five commodities. This was high revenue traffic. And any railroads empty car was fair game to be used.
LCL at least for me and my railroad is alive and well in 53, and looks to have continued that way for some time afterward. Jim Dick - St. Paul
One thing I do need to add about trucking way back. My father was one of those GI's who after WWII drove a truck (for a trucking company) before using his GI benefits to also go to further formal education. He mentioned that trucks were lucky to make 100 mile turn arounds in a full 12 hour day. He drove a truck from Milwaukee to Chicago, and then if everything went right, might drive one back, within 12 hours. Ninety some miles down, ninety some back in twelve hours. Much different than today.
Reading about the Yakima Valley fruit operations in Washington state, the railroads were concerned (in the 50s) about truckers who would bring a load of merchandise east out of Seattle/Tacoma into central Washington state then solicit their services to take a trailer load of fruit back. Competition was on price, not time as shipment by truck was about the same timeframe as railroad reefers took.
That the interstates changed things, I do believe. However I can recall going through Montana in the 1970s and finding areas where interstates links had yet to be built. The interstate act was signed in 1956, this list times out in 1960. For the majority of us, interstates are of no concern when conversing about LCL.