The Dynamite Carrier attachment module makes it possible to blow something up when the cart goes over a Detector Rail. There is no reason to use a hull better than a wood one, you usually don't want to blow up modules or hulls that are expensive.
Put Dynamite in the left slot, the more dynamites you put in the bigger the explosion will be. Max: 50 dynamites. (This can be changed in the configs) Drag the bar to the length of delay you want, closer to the TNT gives it a shorter delay and further away gives it a longer delay. Let the cart roll over a detector rail from vanilla minecraft and it will ignite the fuse. If you look in the cart when it's ignited you can see a red and white flashing bar moving to the right towards to TNT.