Particularly in the case of low-floor LRVs, there are many variations on articulation joints, as each LRV manufacturer has devised its own specific design. These hardware variations can affect vehicle clearances since the pivot points of the articulation can be a considerable distance off of the centerline of sharply curved track. Variations in center section design also affect steering and relative roll, which might have some affect on vehicle curving and rail wear, thus influencing rail steel selection, track gauge, and track superelevation. The track designer has little control over this, but the problem is more difficult with low-floor vehicles using independently rotating wheels than with conventional high-floor vehicles equipped with solid axles.
Existing systems contemplating a change to longer vehicles must consider overall train length and the impact that the revision might have on existing station platforms. Longer cars might require either a reduction of the number of vehicles in a train or lengthening existing platforms.
One major LRT system in the United States initially designed their underground LRT stations for four-car trains of conventional two-section high-floor LRVs. When they added low-floor vehicles, trains had to be limited to three of the longer low-floor cars because the subway station platforms could not be economically lengthened. Longer vehicles can affect other infrastructure and systems as well, particularly the layout of equipment within the light rail vehicle maintenance shop.
There is a common misconception that articulated light rail vehicles can negotiate sharper curves than a rigid body car. This is not true. Rigid cars can negotiate curves that are as sharp, and even sharper, than an articulated vehicle. However, rigid cars are limited in both length and passenger capacity, primarily because the lateral clearances required in curves increase dramatically as the distance between the trucks increases. Where lateral clearances are not an issue, rigid body cars can be appreciably cheaper to procure and maintain than articulated cars of similar passenger capacity; however, this is a distinct exception to the normal circumstances.
In North America, modern non-articulated light rail vehicles are used only in Philadelphia, Buffalo, and Toronto, but, as of 2010, those fleets, which are all high-floor designs, are in their third decade of operation. Outside of North America, the light rail system in Hong Kong and several cities in the former Soviet Bloc have continued to purchase rigid body cars, most likely for reasons peculiar to those systems. Therefore, while thousands of single unit, single-end trams, many of them of designs derived from the North American PCC car, still operate around the world, it is virtually certain that the LRVs for any new system will always be high-capacity, multiple-section, articulated cars.
