A railgun is a series of electromagnets which get turned on and off in sequence to propel the projectile... So…

No. What you mean is a coilgun. A railgun uses a different mechanism, like Wikipedia says:
"A railgun is an entirely electrical gun that accelerates a conductive projectile along a pair of metal rails using the same principles as the homopolar motor. Railguns use two sliding or rolling contacts that permit a large electric current to pass through the projectile. This current interacts with the strong magnetic fields generated by the rails and this accelerates the projectile."

the car wont follow the foil, unless you mean to make slots in wood or something and line it with metal. otherwise you just need to add somekind of switch to increase/decrasese voltage

duhh thats the whole point of a *slot car* but ya I know someone who is writing an equation to determine the resistors needed, and if u already know, we would like around 32-36 volts now cause we used 2 9 volts and it was pretty wimpy.

Yeah but mains is ac but bateries are dc...

 You can reverse the wires to the battery or you can reverse the poles of the magnets...either way it will go in the oppose direction.  

reffer to this picture. looking from the power source, if the (-) is on the left and (+) on the right, it will go forward.

 I understand the force diagram that you have here however for this type of projectile i dont think it is the whole story.  With a classical rail gun this would be true, but  if you reverse the magnets the projectile will move in the other direction (current still flowing in the same direction therefore the force should be the same.  I cant wrap my head around how this is working using the magnets..anybody got any ideas?

 well, its not magnets per se. its an electromagnetic current that creates a magnetic field. the magnetic field creates pressure behind the projectile in the same way a regular gun does with gunpowder. however, this design is different. rather than creating pressure behind the projectile its just repelling the magnets down the strips.
sorry if this is just re-explaining something already known.

Thanks for the post!  I understand what you said however for this case its weird because for the design to work either you would need Both North poles facing out or both south poles facing out.  Having south out on one side and north out on the other will not allow the "projectile" to accelerate.  These field are emmited from the north and would partially travel through the nail and return to there south poles.  I assumed the B-field that is created by the rail is interacting with the field emitted by the magnet..therefore there is a component of B-field from the rail that is closer to parallel with the rail rather than the classical perpendicular to the rail they way a normal rail gun works...the problem I have is when i analyzed the direction of current, applied the right hand rule and  compared it to the inaction with the North or South pole that was facing out..the projectile accelerated in the opposite direction that it should of.   This confounded my  reasoning.  Im out of school for the summer till i start Diff E Q  so i will have a bunch of time to get to the bottom of it an hopefully will be able to put up a diagram that shows the underlying physics of this...Although making this is extremal easy... Its underlying physics seem subtle.  Or mabey i have overlooked something.  Thanks again for your post

what if there was a black out...?

Then you wouldn't be going anywhere fast.

wouldnt matter if there were a black out. They could have it reversed and have the road be a big magnet and the wheels be made of metal and have an electrical charge leading to them and you would increase volts/amps to go faster and decrease it to go slower.

yes that is very true this is an awesome instructable!

true true

monorails do this already, like millenniumman said, and if we did this on roads, it would require more aluminum than you could probably find in the entire solar system... and would need to be continuously replaced as it wore down. Although my question is, why on EARTH ARE YOU TOUCHING THAT THING DIRECTLY?! Iron conducts electricity quite well... wouldn't you be shocked by manually placing that thing on there?

A)he used ALUMINIUM foil not iron B) Its a nine volt PP3 battery. you are not going to get a shock from that.

just a funny taste when you stick it to your tongue :)

Done that before and got a shock...

If there sere only such a thing as a Monorail... lol

Wow that is actually not a bad idea. Three problems though, one all the roads in the world would have to be changed over, there would need to be a way of monitoring electricity consumption to charge people (Electricity isn't free) and what if wildlife or a stupid person walked onto the road, would they get toasted? Creative Idea though.

how about a train then

not a bad idea. there is still problems though

ooooOOOOOooOOOooooOOOOOHHHHH!!!!!!! Thats a good idea! Just need a way to guide the sucker. And away to make it more efficient than a monorail/light rail/other rails.

the rails will guide it

yea, can't recall what I was thinking about there...lol

hence the phrase "theoretically"

Exactly, but you have to admit its a cool idea.

yea, it would cost too much and probably take a lot of maintnance, yada yada yada......

It would add alot of entries to the Darwin awards. I can see it now...... People being dared to lick the road or pee on it or other things I know I can`t post on here.

lolz