CFR Marfă 40 0503-9Gara Fetesti Gara Fetesti

Plenty of container trains in the shot.

Yes... and they stayed there the whole day. The second train (the one in the background) was a "mixed" train: first car was a Rils + a few containers + a lot of T-series cars. There is a third train (containers) that is not visible in the picture and also a 4th train (with tank cars) while a 5th trains was arriving with Ucs cars with cement. However... no freight train left station between 10 A.M. (when I arrived) and 6 P.M. (when I left). There were also some single locomotives, for example this: http://trainspo.com/photo/742/?list=class#photo

Seems like Fetesti is a good place to see freight trains - shame that the trains didn't move very much upon your visit. Is all this stuff going to the port of Constanta?

It is a good place for freight and passenger trains too. There is also a CFR Marfă yard and an Unifertrans Yard there. Most of the stuff is from/to the port, but there are also many trains for the rafinery in Năvodari, for the cemment work in Medgidia and two pairs of trains with calcined alumina from Tulcea. The Feteşti - Medgidia section of line 800 (Bucureşti - Constanţa - Mangalia) is probably the busiest in the country if we talk about freight trains.
Since this picture, most of the Bucureşti - Constanţa line is reapired and practicable (because of the works, some portion were used as a single line instead of double, because one of the lines was under repairs), so the trains should move more than they did in 2008.