Kiso No. 9

This Baldwin 0-4-2RT tank locomotive (class 6-10 1/3 C91) was constructed at Baldwin Locomotive Works in Philadelphia, Pennsylvania in June 1929. It was one of ten locomotives in the final order (of three total orders) built for the Imperial Forestry Bureau of Japan for service on the Kiso Forest Railway, a 30-inch gauge logging railroad operating in the mountainous Nagano Prefecture in central Japan, west of Tokyo and north of Nagoya. The locomotive originally carried the number Kiso Forest Railway #17.

The locomotive was renumbered to Kiso Forest Railway #9 in 19*X* [reason for renumbering unknown]. At an unknown date in the 195*s, the locomotive was exported from Japan and acquired by a private collector, Henry Sorenson, in McKinleyville, California. People familiar with the purchase explain that Henry did not know he was buying a 30-inch gauge locomotive, and was surprised when the locomotive was being hoisted out onto the dock.

The locomotive underwent significant modification for California service: it was converted from 30-inch gauge to 36-inch gauge and restored to operation [date unknown] as Humboldt Northern Railway #11. It was subsequently renumbered to Humboldt Northern Railway #6 in 197*X* (documented by October 1976). In 199*X*, it was re-lettered as "Kiso Forest Railway #6" - an historically inaccurate number chosen for display purposes, as the locomotive never carried #6 while on the Kiso Forest Railway in Japan, but Henry had a number plate with a "6" on it. This incorrect numbering has been perpetuated in various published lists and online databases.

The locomotive operated at Railfair 1999 event at the California State Railroad Museum in Sacramento during June 1999, introducing it to a national audience and cementing its spot in railfan culture. It was donated to the California State Railroad Museum in 1999 and rotated on and off public display from 1999 to 201*X* inside CSRRM's historic roundhouse facility.

CSRRM deaccessioned the locomotive and donated it to SPCRR in 2024 [specific date unknown]. It arrived at Ardenwood in 2024 [specific date unknown] and is currently under restoration to operating condition. When restored, it will represent a rare example of American-made, Japanese forestry railway equipment operating in North America and will add significant interpretive value regarding international narrow gauge technology transfer and the global nature of Baldwin Locomotive Works' manufacturing reach.

Research note: Because the locomotive was incorrectly lettered as Kiso Forest Railway #6 during its California State Railroad Museum display period, it has been erroneously identified as KFRy #6 in various published rosters, websites, and databases. Definitive research confirms it was originally Kiso Forest Railway #17, later renumbered to #9 in Japan, and never carried the number 6 while in Japanese service.

* Unknown date information, closest confident date range used. 
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An in-depth standalone exhibit on the Kiso No. 9 can be found below: