The present disclosure relates to a rail assembly that includes an outer rail and an inner rail opposite to the outer rail. The rail assembly also includes a cavity formed between the outer rail and the inner rail. The rail assembly further includes a first corner reinforcement coupled to the outer rail and the inner rail in such a way that at least a portion of the first corner reinforcement is located in the cavity. The rail assembly also includes a second corner reinforcement coupled to the outer rail and the inner rail in such a way that at least a portion of the first corner reinforcement is located in the cavity.