Ok so a rough count(*):40 wagons by my (rough ?) count - many of them jumbos (4 x TEU). 40 wagons is confirmed by Bevans.
Tanktainer - 7
Not sure what the train length or weight is of course but those numbers look like decent numbers if they can be repeatable. Thats probably close to 40 trucks worth id be very roughly guessing?
(*) based on one count, i could be out by some and am happy to be corrected.
Using your TEU count of 136 plus one (?) empty slot = 138 TEU this equates to a trailing length of about 900 metres depending on the wagon classes involved and using 6.5 metres/TEU on rail. Including roughly 70 metres for the three locos length comes near enough to 1000 metres. Not bad for a start-up service - let's hope that they can keep it up.
It's always good to see extra traffic on rail and off the roads if, in fact, this proves to be the case. I just hope that it is not traffic lost by PN for example.
Is there perhaps any way to 'slow motion' videos like this one so as to gain a much more accurate count etc?