Writing 'as comfortable an electric train' is comparing how this electric train will be running compared to how it is/was running on the previous schedule/format. What makes little sense to me is the last part 'only in the night-time format'. Is the writer trying to say "it is not clear that it will be as comfortable an electric train when it is running in the night-time format" ?? That's th only way I can interpret the sentence. As it is, it doesn't make sense to me.