RZD ER9PK 081Stantsiya Rostov-Prigorodnyy Stantsiya Rostov-P..

I've always liked the curved design of these units. Have you any pictures from the inside?

I have no pictures taken by myself, but here are some examples of both old and refurbished interiors:
https://www.google.ru/search?q=эр9п+салон&newwindow=1&tbm=isch&..h=982
This one no more has old wooden seats.

Many thanks Yuri! Old wooden benches do not look very passenger friendly
I would like to ride on one , just for the experience !

Well, as for me, benches made from single wooden panels ( like this one http://www.train-photo.ru/data/media/335/131-.jpg ) are really something terrible.

But older design where a lot of plates are used ( smth like this http://www.train-photo.ru/data/media/142/IMG_2428_r.jpg ) is unexpectedly confortable. I didn't get tired after two hours ride in such cars. But this old style becomes rare today, and class ER9 is gradually replaced by ED9M and ED9E.