Hi ya TJL and Welcome to GameBoomers
Thanks for welcoming me here.
This site has been my number one source of walkthroughs for years.
I have googled and read several walkthroughs for this particular problem including the one on this site.
None of them describes the events in every detail. I assume that after Hyde has fixed the rail and you click the "Hand" icon as Jekyll again, the next sequence shows you and the wagon by the tunnel entrance. If you haven't already attached the light then clicking "Magnifying Glass" icon asks you to do so. Should you then use the crowbar or is clicking "Hand" icon enough? For me there is no option shown in the Inventory to use the crowbar, should there be?
I have tried starting the game from several earlier savepoints but nothing seems to help. I always lack means to enter the tunnel with the wagon.
My game version is a download version from Adventure Shop US. There is no patch available there, already checked it.
I hope some of you having played the game through is able to help me with this problem. By offering a save game if there is no other way to pass this problem.