The last item that can be researched each era in the lab is Coupling. Coupling allows you to haul goods with engines from previous eras.
The level of your lab determines how quickly Research Points are generated and how many you can store before they must be applied.
With a Plus account or researcher, RP generation is 25% faster.
Members of Iron Horse should be aiming to reach Coupling in all eras.
Where should your lab be by the end of an era?
About Calamity
Extremely helpful. A pity this site seems to be dead. Wish you luck if you’re still playing. You’ll be number 1 plenty of times I’m sure.