Next I need mass. Each vehicle has an empty weight of 26,000 kilograms and a capacity of 34 seats, or 123 passengers. Judging by the video, the train looks quite crowded, but not at full capacity. Let’s say there are 60 people in the car, and each rider has an average weight of 70 kilograms.
Finally, I need the total number of carriages. We never get a perfect shot, but I’m guessing there are five cars. Thus, the total mass will be 151,000 kilograms. Taking this mass and acceleration into account, we get a stopping force of 113,000 newtons.
This is the overall force that pulls on the train to slow it down. But remember that there are cobwebs on both sides of the train. Since Spider-Man is holding onto the web on both sides, he is essentially just applying a force equal to the tension of the web. This means that he only applies a force that half total stopping power.
The same thing happens when you pass a rope through a pulley: this allows you to double the tension. (The spider essentially acts as a wheel in a pulley system.) Spidey’s applied force would be half of 113,000 newtons, or 56,500 newtons. If you want to convert this to imperial units, it would be 12,700 pounds. It’s like holding a male African elephant. You can see my calculations here.
I’m going to rate Tobey Maguire’s Spider power equal to at least 56500 newtons. Of course, we don’t know if this is its maximum limit, but it is at least a starting value. Besides, I must admit that I may have cheated. I assumed that the force Spider-Man exerts on the train is constant. This is probably not the case. If webs are like rubber bands, bungee cords, and other elastic things, the more you stretch them, the more force it takes to hold or pull them. But since I don’t have any evidence that these webs behave like bungee cords, I’ll just stick with my estimate of the constant force.
Keeping the split steam together
Now we can move on to Holland’s version Spider-Man: Homecoming which you can see in this clip. After an alien weapon explodes and splits the Staten Island Ferry in half, Spider-Man struggles to patch the boat with his webbing to keep it from sinking. But it slowly begins to separate: the two halves crack lengthwise, and some of the webs holding them are torn. In desperation, he grabs the web attached to both sides and tries to put the ferry back together. I drew a sketch of the important part (not to scale).
Illustration: Rhett Allen