Based on our research it looks as though Pan Am had ordered this Electra (1019) back in 1933 but it wasn't delivered until April 1935. Pan Am gave this aircraft to their Pacific Alaska Airways division with registration NC14906; eventually it was transferred to Cuba's National Aviation Co., Cia Nacional Dubana de Aviacion and the markings changed to NM-26. The registration changed again to NM-12 and the aircraft was converted to a Lockheed Electra 10E; from there the aircraft jumped around to many different private hands. The last registration we have for this aircraft is N2628 in Alamo, Texas.
In the course of our research we did come across a movie clip of this aircraft from the 1940 short film "Sitka and Juneau: 'A Tale of Two Cities.'"
Sitka and Juneau: 'A Tale of Two Cities' (1940)
NC14906 and a dog sled team
Postcard of the Electra with Mary Hansen and her Siberian Team