NORTHERN Rail has announced a series of train cancellations due to signalling problems. 

Earlier it posted that due to signalling problems between Sheffield and Meadowhall some lines were entirely blocked. 

Now the 13:48 Leeds to Sheffield due 15:02 is cancelled as is the 13:40 Leeds to Sheffield (that was initially expected at 14:37). 

There are also delays between Sheffield and Doncaster until later today.