If you want to get normal way then you go to that construction building, go to second floor, find a hole there and then deliver it to the green pipe where the train track is
So this just a glitch the real way is to go to the second floor in the construction site and grab the portable hole then you put it on the mario pipe and jump in and you get the text on your screen saying holes are holes when you get in go to the air vent thing,jump in the white box with a fan then get through the air vent and get to the end.
Guys it’s the wrong way u are not supposed to go through that car tunnel u should go to pile and grab a potable hole for construction site and put it on the green pipe then u can fall in the pipe and now when ur done Dat u follow his steps
This still works in 2021 but there is a ez way go to the building next to the crane this on the 2nd floor go to the but lick the black circle is a portal then go to the green pipe and put it on there and thats the normal way