Pggyback, Roadrailer, etc. seems to have fizzled here. Others more knowledgeable probably know why. Maybe distance and our distributed population centres played a role. I imagine by the time it takes to assemble a train in Montreal a truck could already be in Toronto. Also, with such a low level of domestic manufacturing, a lot of our non-bulk cargo is already in a container at a port.
TOFC has been declining for years as it far cheaper to stack and store containers than trailers. It also cheaper to built the trailer for containers than trailers as trailers.
Unless you are shipping over a 1,000 miles, cheaper to use the road than rail.
Some business may have a number of cars on a siding at any given time as they act as storage cars until X is needed from them and then replace by another set as needed. Mostly hopper and tank cars are use for this service. Box cars are off loaded/loaded fast as they can so another set of cars are brought in.
You still see the Roadrailer around, but not as much in the past as well being a lot shorter trains. Don't know if CN still running the Roadrailer these days after taking over it from CP and CP dropping the Ironrail service.
Trucks today are mainly on time demand service since most places have little warehouse space compare to the past and RR is still not at this level with exception of a few specials runs.
There is one transport company that see very few trailer up here compare to the past and one of the largest in NA. Even when train watch in Buffalo, was seeing very few of their trails as well containers on trains. Don't see much TOFC on Buffalo trains for some time or other parts of the US.
You need one item per trailer to use rail and some trailers are containing more than one item on the road