Framing Frame, Day 2
Day two tasks you with switching the paintings for a cash. This is probably the easiest of the three days.
Start by answering the phone, and you'll be asked to place the paintings onto the table. Follow the rest of the phone instructions, and the pickup chopper will arrive momentarily. Trade the paintings for cash, and prepare for a police assault. Your current position inside the train car is a good place to hold out, so drop Doctor and Ammo bags and brace for the attack.
When the smoke clears, run those bags of money to the escape van as quickly as possible. If you have more than one per player, daisy chain them. This job is nothing but moving money and shooting cops, so just keep pushing until the job is done.