The world's largest operating steam locomotive will join with the only mainline U.S. steam locomotive never retired to take a trainload of several hundred passengers from Salt Lake City to Sacramento this week, part of a locomotive roundup from all over North America and Great Britain for Railfair 91.

The Union Pacific locomotives, joined together and originating in Cheyenne, Wyo., are scheduled to arrive in the South Sacramento Union Pacific Railyard at 6:30 p.m., Saturday, April 27.Some of the historic locomotives will arrive under their own steam, others by truck, flat car or (from Great Britian) ship, for a total of 30 historic steam locomotives.

Friday, May 3, through Sunday, May 12, the cobblestone streets of Old Sacramento will be transformed into a temporary museum showcasing the history and future of railroading - the largest gathering of historic railroad equipment in some 50 years.

In addition to the arriving locomotives, the California State Railroad Museum's existing collection of 21 restored locomotives and cars will be included on Railfair's 15-acre grounds along the Sacramento River.

In addition to the locomotives, Railfair 91 will feature a railroad musical revue, toy train display, railroad track lining gang, an educational "Junior Engineer" program for kids and other activities.