There is already a mod like that in the workshop , i think created by Flash , a escalator with higher capacity . For that you need a script , and i'm no script modder. But Flash and QCS do that. here is the link to the mod:
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=2120916161&searchtext=Fast

pls make better stair case mod like one that allows more passenger to go up/down but takes up same space