If you are wondering what the Baker Viaduce might be or, more importantly, why the traffic on Huddersfield Road through Ravensthorpe is so appalling, then this might explain what is going on.
In essence, the new viaduct will reduce the curvature of the bend out of Ravensthorpe allowing trains to run faster. The new, additional lines running parallel to the existing lines will allow fast trains to run without being held up by slower, trains that stop at every station and the relocation of Ravensthorpe station will allow Dewsbury residents to catch a London bound train out of Ravensthorpe without the dog-leg via Leeds.