CJ happens upon Ryder doing some “cooking,” when Tenpenny and Pulaski arrive to give them a hint at something. There is a train passing through with something good for you, so it looks like you will be robbing it. You will automatically enter Ryder’s vehicle, so you will be driving to the train now. Upon arriving, you find some Vagos are already there, so get out and gun them down, being careful about your one Grove Street member already being in battle. If you left the vehicle too quickly, you’ll have to get back in it and get close until there’s a little scene. If you killed the Vagos already, then some Ballas will roll up, so kill all of them now.
When the coast is clear, go hop on the back of the train to find that the train will resume running. Ryder will be driving right behind you and CJ will have to toss the crates to him on the back of his truck. Hold down the button shown in the instructions to power up the throw, then release it to toss the crate. Despite Ryder’s complaint about throwing it too hard, it doesn’t really matter, as he will catch the crates. Thus, you should aim the reticle directly at him or slightly above his head to get the crates on target. You have to get ten crates to Ryder, but should you miss, you will see the crates explode.
Thankfully, you can’t blow up Ryder’s car here, so don’t worry about that. The train will go around bends and stuff, so your path isn’t always going to be a straight one. Once you do land the tenth crate to Ryder, then CJ will get off the train and automatically get back in Ryder’s vehicle. Unfortunately, things aren’t over just yet, as you will receive a three-star wanted level, meaning that the cops will be coming after you a little more forcefully than normally. Thankfully, the Pay ‘n’ Spray you will need to use is marked on your map, so head there to get the heat off of you. Once you’re done there, drive back to Ryder’s house to finish the mission.