Tripled pawns on the same file can cause immobility
Doubled pawns are 2 pawns sharing the same File on the board. Like Isolated pawns, they are a hindrance because they block each other from moving. Usually doubled pawns do not have any other pawns defending them, so they are prime targets. They also have a limited range of attack. If there are three pawns stacked on a File, then they are called tripled pawns.
Doubled pawns are often the results of trades or gambits.