Modernity and History
Symbolism, Imagery, Allegory
Another effect of all the science and technology in Dracula is to create a contrast between modernity and history. You can read Harker & Co. as Team Modernity and Dracula himself as Team History.
Dracula is, after all, centuries old. He lives in a crumbling old medieval castle, and the surrounding countryside is filled with superstitions and traditions. Jonathan Harker describes his travel from Britain to Transylvania as being like a trip back in time, and that transition is represented by (surprise, surprise) the punctuality of the trains.
The further he gets from Great Britain, the center of modern civilization (in Harker's opinion), the less reliable the trains are. So Count Dracula could be seen as representing history or the past, and Great Britain as representing the present. If that's the case, maybe Dracula's "invasion" of Britain is meant to remind us of the way history has of influencing or haunting the present.