Rail parts distributor Wabtec Corp. (NYSE: WAB) has bought Relay Monitoring Systems Pty Ltd. (RMS) for an undisclosed amount.

The target makes control relays and other sensor systems for the rail and energy sectors. RMS, based in Mulgrave, Australia, has about $15 million in annual sales.

“RMS is an excellent fit with our existing Mors Smitt business,” says Wabtec CEO Raymond Betler. “Together, the companies offer complementary products and geographic presence, which we believe will result in superior growth opportunities for both.”

Wabtec, based in Wilmerding, Pennsylvania, has been active with acquisitions lately. In 2015, the company bought sensor systems manufacturer Track IQ and transportation parts maker Faiveley Transport SA. Wabtec also recently purchased signal construction services provider Railroad Controls LP and in 2014 it bought data collection product maker Fandstan Electric Group Ltd.