Question: Casey Jr is the train seen in a film released by who?

Context paragraphs:
How to Train a Dog: How to Train a Dog is a 1936 short film released through MGM Studios starring Robert Benchley.  The short film demonstrates how not to train a dog, following Benchley's character getting the dog from a pet store.

Ken Casey: Kenneth William "Ken" Casey Jr. (born April 15, 1969) is the bass guitarist, primary songwriter, and one of the lead singers of the Boston Celtic punk group the Dropkick Murphys.  Casey was one of the original members, starting the band in 1996 with guitarist Rick Barton and singer Mike McColgan.  He is the only original member of the Dropkick Murphys left in the band, though drummer Matt Kelly joined shortly after formation in 1997.  He is known for his melodic vocal parts and solid punk rock bass playing.  Dropkick Murphys released their ninth album "11 Short Stories of Pain & Glory" on January 6, 2017.  Casey also founded the charity group The Claddagh Fund, owns his own bar in Boston and runs his own boxing promotion called Murphys Boxing.  Casey has a small role in the 2016 film Patriots Day which is about the 2013 Boston Marathon bombing and the subsequent terrorist manhunt.

Pennsylvania State Treasurer election, 2008: Pennsylvania's election for Treasurer was held on November 4, 2008.  Democratic incumbent Treasurer Robin Wiessmann had been appointed by Governor Ed Rendell to fill Bob Casey Jr.'s term when he was elected to the U.S. Senate in 2006; Wiessman's appointment included the condition that she would not run for election in 2008.

Samuel B. Casey Jr.: Samuel Brown Casey Jr., (October 4, 1927 – October 12, 2006) was president of Pullman Company in the 1970s, leading the company through a series of company operation unit spin-offs.

Casey Jr. Splash 'n' Soak Station: The Casey Jr.  Splash 'n' Soak Station is an attraction in the Fantasyland section of Walt Disney World in Bay Lake, Florida.  Casey Jr is the train seen in the film "Dumbo", where Dumbo, his mother, Mrs. Jumbo, and other circus animals travel on to the shows.  This attraction is a water play area across from the Dumbo the Flying Elephant ride and The Barnstormer starring the Great Goofini.  It is designed to look like it has actual animals in the train by having elephant trunks and giraffes that spray out water at young guests.

Casey Jr. Circus Train: The Casey Jr.  Circus Train is the name of a ridable miniature railroad attraction found at Disneyland and a powered roller coaster attraction found at Disneyland Paris.  Based on the train of the same name from the 1941 film "Dumbo", it gives passengers a tour of many miniature versions of classic Disney animated film scenes.  This tour is similar to the one given on the slower paced Storybook Land Canal Boats, but does not incorporate narration.  The original attraction was operating during the grand opening of Disneyland on July 17, 1955, but was closed the following day for safety testing and reopened on July 31, 1955.

Destination Victoria Station: Destination Victoria Station is a 1975 album by country music singer Johnny Cash.  It was offered as a CBS Special Product and could only be bought at Victoria Station restaurants.  Cash re-recorded many of his old train songs for this album, including "Hey Porter", "Casey Jones", "Waitin' for a Train" and "Wreck of the Ol' 97", as well as recording two new songs, "John Henry", and "Destination Victoria Station".  In addition to re-recording songs, Cash also re-recorded his voice on "Wabash Cannonball" and "Orange Blossom Special", both retaining their original backing music.  To date this album has never been released on CD and it was omitted from the otherwise-comprehensive 2012 box set "".

Dumbo: Dumbo is a 1941 American animated film produced by Walt Disney Productions and released by RKO Radio Pictures.  The fourth Disney animated feature film, it is based upon the storyline written by Helen Aberson and illustrated by Harold Pearl for the prototype of a novelty toy ("Roll-a-Book").  The main character is Jumbo Jr., a semi-anthropomorphic elephant who is cruelly nicknamed "Dumbo".  He is ridiculed for his big ears, but in fact he is capable of flying by using his ears as wings. Throughout most of the film, his only true friend, aside from his mother, is the mouse, Timothy – a relationship parodying the stereotypical animosity between mice and elephants.

Under Siege 2: Dark Territory: Under Siege 2: Dark Territory is a 1995 American action film set on board a train traveling through the Rocky Mountains from Denver to Los Angeles.  Directed by Geoff Murphy, it stars Steven Seagal as the ex-Navy SEAL, Casey Ryback, and is the sequel to the 1992 film "Under Siege" also starring Seagal.  The title refers to the railroading term that the subject train was travelling through dark territory, a section of railroad track that has no train signals and in which communications between train dispatchers and the railroad engineers were impossible.

Boys in the Sand: Boys in the Sand is a landmark American gay pornographic film released at the very beginnings of the Golden Age of Porn.  The 1971 film was directed by Wakefield Poole and stars Casey Donovan.  "Boys in the Sand" was the first gay porn film to include credits, to achieve crossover success, to be reviewed by "Variety", and one of the earliest porn films, after 1969's "Blue Movie" by Andy Warhol, to gain mainstream credibility, preceding 1972's "Deep Throat" by nearly a year.

Supporting paragraphs: Casey Jr. Splash 'n' Soak Station Dumbo
Answer: RKO Radio Pictures