Module 1 is very wide ranging; there is no substitute for experience- it is pretty much impossible to learn out of books alone.
Having said this, then yes the
Yellow Book is probably the place to start- there was a time about 5 years ago when this alone may have got you through the exam but you are correct that the exam is now better at making sure candidates really understand and can apply and the Yellow book itself is abstract and high level.
You have got to get used to thinking how to apply to real situations- this can be in your day job, working through the Module 1 Study Pack, attending a Study Group discussing and actually attempting past questions.
You also need a wide domain knowledge, so I wouldn't do this module until you've already got two others under your belt. It is clear from your bio details that this is exactly what you have done so that is good. You have however given only a brief idea of your background and experience, but those people that have had some form of wide ranging training scheme when joining the industry that find they can do it without too much difficulty. If you have only experience in one part of the lifecycle (e.g. pure signalling designer rarely getting out of the office, or maintainer always dealing with faults in real time) then you'll struggle unless you take stps to broaden from your pure job role- your employer may be able to help a bit but some of this will need to be extra-curricular.
So yes you do need to read widely (e.g. lots of articles in IRSE News) but not just passively but having the background of the Yellow Book and seeing the links to it as you read. Note that although there is no "module 1 text book", there are items available that help if you look for them- there are portions of the Module 2 Study pack that have a distinct "module 1 spin" and the TPWS paper I wrote for the YM a couple of years ago is probabl;ly more Mod 1 than Mod 5. On this site there are already some suggested mod 1 answers which I assume you have already found.
Also attend lectures, events, visits and most of all Study Group; if you can't get to a physical one then use this website as one- attempt a question and post it to encourage debate, alternative views and feedback.
regards,
PJW