* 700 unionized workers walk off jobs
* CAW says talks broke down over pension changes
CALGARY, Alberta, Aug 9 (Reuters) - Workers at Bombardier Inc's (BBDb.TO) Thunder Bay, Ontario, operation went on strike on Tuesday after negotiations broke down.
About 700 workers represented by the Canadian Auto Workers Local 1075 walked out at 4 p.m. local time after talks fell apart over the company's demand for cuts to the pension plan, the union said in a release.
The previous contract expired at the end of May.
The company's operations in Thunder Bay, on the shore of Lake Superior in northwestern Ontario, produce bi-level rail cars, as well as streetcars and subway cars.
Bombardier's class B shares rose 31 Canadian cents to C$5.21 on Tuesday on the Toronto Stock Exchange.
$=$0.98 Canadian Reporting by Scott Haggett; editing by Rob Wilson