I was watching container trains go by here in Palmyra,NY and was wondering about the drawbars on the well cars. Reading in a past issue of trains the drawbars on the flatcars of a van train was for carring more trailers. Now what are the drawbars for a well car is for.
When the train gets to port the railroad is charged for each CAR they bring into the facility. So if they use three well cars they get charged for three cars but if they connect the three with drawbars and give them all the same number they they only get charged for ONE car not THREE. That is a 66% discount. What a scam, eh?
IIRC, many container units are actually multiple cars permanently linked with drawbars (vs couplers). Five seems to be a common number for some reason. Since containers usually run in what amounts to unit trains anyhow, it makes sense to eliminate four sets of couplers (on a five car set) and the headaches they bring along.
I believe there are also articulated sets - two cars sharing one truck (except on the ends).
There is also the benifit of less slack action.
Another reason why they are also drawbared together is in additon to reducing slack action it also allows the full capicity for each unit without going to couplers on each end the old articulated unit could not carry the full 125 tons in each unit.
Articulated well cars usually have a capacity of 120,000 lbs, while drawbar connected well cars (and stand alone wells) have a capacity of 160,000 lbs, e.g. increased load factor. Two 70 ton trucks can carry more than one 125 ton truck.