Restoring my All Nation F3 & F7 Locomotives, in all cases these engine kits did not come with fuel tanks. What served was the outside tank sides cast into the engine body. The result was a wide open space underneath the engine. Depending on the type of power purchased with the engine kit from All Nation, one could have had a single truck power or dual truck powered and a tank would fit nicely with a tower drive. Some guys may have even re-motored the power in later years or configure a drive shaft from one truck to the other in which case a tank might have conflicted with the model's operation. Almost all my CGW engines are going to get a fuel tank very soon. This kit for sale is for the F3 or F7 un-powered A & B Units. I have found working with these models over the years there are slight variances which is particularly evident more so with the F A Units where upon examining for example the power truck platforms, a little sanding along the edges would have been done on the Bakelite or widening of the screw holes. I have taken inside measurement samples between the tank aprons across all my engines and in my case the B units always come in at approximately 42 mm wide. My A units measure any where from 41 mm down to 40 mm wide. Consequently, if this kit is used on an A unit that is less than 42 mm, some sanding equally of both sides should be done slowly and carefully so the tank fits snugly into place. The platform the tank mounts to should not require sanding as it sits higher up inside the body without any constraint. The main tank pictured here is empty of material because I have in mind to use the space in the B units for sound, speakers and potentially Power On Board batteries. Rather than simply gluing the tank in place and nothing says you can't do that, this kit comes with a floor to mount the tank to the floor with 6 4-40 3/8" screws which then the floor mounts to the power truck platforms that also comes with this kit to replace the original Bakelite platforms. The holes on the ends of the floor may or may not match up with your particular power truck platforms if you stay with the original platforms. In order to put this kit together, you will need a #43 tap drill bit and a 4-40 tap. This kit comes with a total of 18 4-40 brass flathead countersunk screws. Some very minor clean up of fine threads from the printer maybe required. The depth of the pilot holes on the tank are approximately 5.5 mm deep. The space between the tanks may need to be filed smooth of some material removed to level with the split in the casting using your discretion. Printed with 100% Infill PETG filament sold as is straight off the Prusa Printer built plate, all sales final no returns. Made In The USA.