I'm a bit confused as to what sort of crane you want to model. There are three different types used in intermodal service in the United States, and all three are different from each other in various ways.
#1 is the "hammer head" crane that is used to load/unload containers from the ships to the utr trucks & chassis. This is the biggest of the cranes used in intermodal service. The basic structure is a pair of modified "A" frames. The two "A" frames will be approximately 60 feet apart with cross members connecting them together at the top of the "A" and at the bottom of the legs. It is pretty much open in between to allow containers to be lifted off of chassis and trolleyed out over the ship's deck without interference. It will gantry along the dock on two rails set @ 30 or 40 feet apart if I remember correctly. The boom is hinged and swings up like a draw bridge when not in use, or when the crane needs to gantry past the ships bridge. The basic crane framework could be modeled using Micro Engineering structural "I" beam shapes of various sizes. You could use a Pikestuff metal building for a machinery house. The machinery house sits about 100 feet up on the cross members of the 2 "A" frames, and will measure about 40 feet by 60 feet. The house is mounted behind the "A" so that it will counter balance the weight on the boom when lifting a loaded container from the far side of the ship. The largest container ships are probably 200 feet wide, and the boom has to reach all the way to the far side. The machinery house is mounted solidly to the frame. A trolley operates on rails on the boom with a glass cab mounted to the bottom of the trolley. The cab could be easily modeled with clear styrene and Micro Engineering "L" structural shapes. The cab is probably about 5 feet square, with clear glass on all sides except the top and back, and the very back part of the floor where the driver's seat is mounted. The front of the floor is sloped up like the floorboars of a car, and all glass so the operator has a clear view of everything below him. The containers are lifted and lowered by a device called a "spreader bar." The spreader bar is a rectangular frame 8 feet wide that extends to 40 feet long or retracts to 20 feet long. On the corners of the spreader bar are twist locks that fit into the corner posts of the containers and then twist 90 degrees to lock into the top of a container. Overall size of the "hammer head" crane will be 60 feet long, 200 feet tall at the top of the "A", and 300-400 feet from the back of the machinery house to the end of the boom. The crane gantrys by use of electric motors mounted to each wheel on the trucks. The motors will be veritcal at the far ends of each gantry truck. Hoist and trolley are accomplished through cables on drums in the mnachinery house going through sheaves. The boom cables use to raise and lower the boom come out the front of the machinery house near the roof and go all the way to the top of the "A" and out to the end of the boom.
The 2nd type of crane used is called a "transtainer." That is the crane picture in the both links in the thread except that we don't use a prototype like that in the U.S. All of the transtainers in the U.S. run on huge rubber tires, similar in size to the ones used by construction equipment. The drive is by electric motors at each wheel driving through a chain from a sprocket on the end of the motor to the wheel. Each of the four wheels is on a pivot which allows all 4 wheels to steer. The motor, drive chain, & wheel all pivot together. When I last worked in the Harbor in the late 80's the largest transtainers would stack containers 4 high and 5 wide with room for a truck lane underneath and lift 5 high to clear the stacks. They are about 50 feet long to clear 40 foot containers. There is a machinery house between the legs on one side that houses a diesel engine and generator set to drive everything. Also on the same cross member with the generator set is a fuel tank. The other side of the transtainer has an electrical cabinet to control everything.
The 3rd type of crane used in intermodal service at railyards and on docks that have direct railroad access is the straddle crane. It was not pictured in any of the links. It looks like the transtainer but is much smaller.It is usually 2 lanes plus a railroad trrack wide, and just tall enough to stack containers 2 high in double stack cars. If found on dock it will just have a spreader bar, because all containers are loaded using twist locks from the top of the corner posts. At the rail yard it will have 4 long arms that will swing down to grab the bottom of a trailer because the railyard crane is designed to load both containers with twist locks as well as trailers in piggy back service. The only crane used in intermodal service in the U.S. that runs on rails is the "hammer head". The rest of them run on rubber tires because they are more versatile that way.