Railroad operator Norfolk Southern said it planned to hire 500 employees by the end of the year, bringing total additions for 2011 to more than 4,000, and plans to add 2,600 employees next year to meet growing freight volume and replace retiring workers.

The open jobs this year are in eight states, and openings include conductors, machinists and maintenance workers, the Norfolk, Virginia-based company said in a statement.

Norfolk Southern operates about 20,000 track miles in 22 states and the District of Columbia.

The company had nearly 29,000 employees at the end of 2010, according to its website. (Reuters)