NSE is an organization "dedicated to the preservation of the history of N Scale Model Railroading, and the railroads they represent". And apparently part of what they do is release N scale models - some simply being custom repaints of other manufacturers' models, and others (like this one) being full-blown custom projects.
Here's what NSE has to say about their 2017 helium tank cars -
Helium tank cars were some of the heaviest railcars ever made (weighing in at at 240,300 lbs empty, and with a 28,000 lb load limit). Built in 1961, these cars were initially used by the BLM to transport helium from mines in Texas. Later, many (13) of the cars were transferred to serving NASA Titan rockets and the space shuttle (up until the last flight in 2011). A few cars have been repurposed for use in the Space X engine test complex outside McGregor, Texas. Eight other cars were transferred to California and are on lease to support the Space X Falcon 9 launch complex at Vandenberg AFB.