I am pleased to report that Agatha Christie: Murder on the Orient Express is indeed an excellent adventure game suitable for beginners (myself definitely included in this category). I'd say I solved about 90 to 95 percents of the game without resorting to walkthrough (*). I just did not know what the heck ham radio was, much less about how to assemble electricity power *generator* for it
(*) Note: Adventure game experts may laugh at this, but for an adventure beginner like me, solving 90-95% of the game without consulting walkthrough as I usually do, means a lot.