A colonel rank in the army is the most senior grade for a field military officer. This rank lies above the Lieutenant colonel rank. Above the colonel’s rank, lies the rank of a brigadier general. If compared with navy, the rank of a colonel is almost equal to the rank of a captain in other services.
Most People are not able to go above this rank because it gets really competitive after this. After all, the number of brigadier generals is far lesser than the number of colonels that can be appointed. This is the prime reason why most army personnel are able to reach the rank of a colonel only.