Trolley poles are known for their ability to handle much greater off-center wire positions than pantographs. This raises the question: How much off-centering can pantographs handle?
Any place in the flat surface, between the horns. Actually, some side to side stagger of the trolley itself is better for any wear of the pantograph.
In some instances. Not all. Variations in track alignment, temperature extremes on catenary and support structure, etc, can be enough alone. For example, from the day it was insalled, MILW trolley was never zig-zagged.
And on curves, the wire makes a straight line (in the horizontal plane) between posts, so it doesn't exactly follow the centerline. I had been looking for / expecting some value from some kind of manual: an electric locomotive operator's manual, or a railroad's specifications for installing catenary... My main reason for asking: If you had a dual-gauge railway (3-rail, not 4-rail), would it be feasible to run electric trains on both gauges (assuming a common voltage) with a single overhead wire? Or more accurately, for how great of a gauge difference could one expect this to function?
In Europe there are national standards about pantographs and catenary lines, that means that, even if the current is the same (voltage, DC/AC, frquency) sometimes there have to be different pantographs (or there are limitazion in current draw or speed). An example is between Switzerland and Gemany, if I am not mistaken swiss poligonation (zig zag) is far borader than german one. That is the reason why most interoperable (multisystem) locomotives come with three or even four pantographs. For Triplex, I do not know of mixed gauge lines with a single overhead for BOTH lines, however, I may think that the easiest way to cope with this is to use four rails, in any case you also have to take care of the height of the wires over the track that can be unsuitable with the loading gauges. Pantograph versus trolley, I think that the main issue is speed, pantographs are more stable at high speeds and can draw even considerable currents, here we talk about 2000 Amperes at 250 kph on the old 3KV DC lines, and there are studies to increase speed to 275kph (higher speeds require at the moment 25KV AC lines)
