From mid 1960's to date
Past and present roads.
I believe the Pennsy was the first to contract for them.
It can eliminate the need (but not the option) for placing coils in gondolas or on flats. They can easily co-exist.
I'm considering a 'steel drag' unit train of them, mixed with gons and flats (not terribly prototypical perhaps, but kinda' cool).
ScaleTrains, ExactRail, InterMountain, Atlas, and Walthers produce excellent highly detailed examples.
Mostly all-metal bodies, with removable plastic hoods... very easy to add weight.
These are InterMountains.
Past and present roads.
I believe the Pennsy was the first to contract for them.
It can eliminate the need (but not the option) for placing coils in gondolas or on flats. They can easily co-exist.
I'm considering a 'steel drag' unit train of them, mixed with gons and flats (not terribly prototypical perhaps, but kinda' cool).
ScaleTrains, ExactRail, InterMountain, Atlas, and Walthers produce excellent highly detailed examples.
Mostly all-metal bodies, with removable plastic hoods... very easy to add weight.
These are InterMountains.