Official photograph, therefore anonymous, and copyright expires 70 years after first publication. It is reasonable to suggest that this took place in 1935, the year of the engine's construction and was published in railway magazines or in-house journals.
This image (or other media file) is in the public domain because its copyright has expired.
This applies to the United States, Canada, the European Union and those countries with a copyright term of life of the author plus 70 years.