What train is this?

[Mudkip Orange]

It seems to always be pulled by a DD-51, regardless of whether there's electric or not.

 

[stevenh]

http://www.jnsforum.com/community/topic/8117-jr-west-special-cruise-train/

[miyakoji]

Yes I suppose it falls into the cruise train category, but specifically the passenger car set is called the Salon Car Naniwa. The second video calls it the Salon Car Kii, but that's just because it's on an excursion in Wakayama-ken, which along with part of Mie-ken was Kii province before the establishment of the present-day prefectures. Tetsudou News had this item about it recently:

 

http://railf.jp/news/2014/12/07/191500.html

 

Japanese Wikipedia page about the Salon Car Naniwa:

 

http://ja.wikipedia.org/wiki/%E3%82%B5%E3%83%AD%E3%83%B3%E3%82%AB%E3%83%BC%E3%81%AA%E3%81%AB%E3%82%8F

[ozman2009]

Smart looking coaches!

[yakumo381]

Naniwa set is usually stabled at Miyhara depot by Shin-Osaka Station...but always in a difficult position to photograph!

[Mudkip Orange]

The second video calls it the Salon Car Kii, but that's just because it's on an excursion in Wakayama-ken

 

That explains why I've seen this trainset with different headboards on the locomotives. There also seem to be more videos with it running as a five-car set than as the full seven cars.