Thanks for your help, in the end did not make it to Hanover as we had every day with 3 or 4 hours sunshine in Wernigerode, and the rest of the network excluding the Brocken which was in cloud every day. There was no snow anywhere in low lying areas and what little there was in places like Alexisbad and Benneckenstein melted while were there.
On the Monday we hit lucky as the green mallet was on a Wenigerode to Nordhausen special, hired by a group of Dutch railway enthusiasts who had hired it for the day. I asked politely if they would mind if we followed th train to photograph it and they were very pleasant and had no problem in us doing so , even during their organised run pasts.
One thing i did notice was that people were asked to leave the yard at Wernigerode during the day, this being further confirmed by the car park barrier at the Imbiss car park opposite the sheds now having a full level crossing type barrier as opposed to just the pole you could duck under.
We had a day in berlin on the Wednesday coming home and again were lucky with the weather, would heartily recomend a climb to the top of the Berliner Dom, well worth the 7 euro entrance price as it is, but views of the line from Alexanderplatz are superb, be warned, think it was 272 steps to the top.
So 882 raw files now to be poured over and edited, will post the link to my flikr site when done, could be a long time lol.