|an explosive box car|
Let's examine the car.
It is an all plastic affair. Kind of short and small compared to the 6400 series of boxcars from Post War. Everything barring the axel is plastic. Stickers for nameplates and graphics. No build date. No moving doors. No doubt this is a cheap car which possibly came in a set during the MPC era.
The only indication this is a Lionel product is raised stamped lettering on the coupler sider "Lionel 9000 Series."
This is our first bit of evidence to work. And nothing comes of it on the Net. However the mold of this car certainly resembles quite a few catalogued cars. The Toys R Us 9045 and the Hershey's 9041 must share the same mold. It also appears to be a close relative of the Post War era Baby Ruth x1004.
Nothing comes for Acme Explosives Company either. I surmised it may have been part of a Looney Tunes set but that search produced nothing.
So this boxcar's origins will remain a mystery.
Update- May 9th 2013.
Poking around on E-bay I think I discovered where this car came from-The Black Cave Flyer set. It was a pretty cheap Lionel outfit from 1982.