The acquisition contract was signed on 5 December last year.
Rocla manufactures pre-stressed concrete railroad ties and turnout ties for Class I railroads, commuter passenger operations and transit authorities.
Rocla Concrete Tie CEO Peter Urquhart said: "We have been fortunate to work with Altus Capital Partners in strengthening Rocla’s growth platform over the last three years.
"Russ Greenberg and his team brought more than just financial resources to the relationship; they worked hand in hand with our management team on both strategy and tactics, demonstrating their commitment to our growth as real partners."
Altus has previously invested in Rocla’s growth with two acquisitions, two new facilities and plant expansion. This allowed Rocla to expand its reach in the US and Mexico.
Vossloh Group CEO Dr Hans Schabert said: “The acquisition of Rocla enhances our profile as a provider of integrated comprehensive solutions for rail infrastructure customers, while at the same time strengthening our position in the focus market USA.
“Rocla is firmly established in the US market and serves the most important customers in the US rail industry. We would like to extend a warm welcome to our new employees as part of the Vossloh Group.”
Rocla was acquired by Altus as the company had plans to participate in the expected need of durable concrete ties that reduce maintenance and prolong rail life within the US railroad industry and also globally.