The 3820 USMC with operating 3830 submarine was included in the famous 1805 Land Sea and Air gift pack by Lionel Corporation.

The submarine is a 3830 US Navy Sub as no separate 3830 sub was made by Lionel. 

The sub was held in place on the olive drape flatcar by the means of two [2] metal clamps that the underneath of the sub slid onto.

This submarine is highly prized as it has a two level equalizer.

Care should be exercised when purchasing a sub unit as many reproduction units exist. Insure that Lionel is clearly evidence on the clear plastic underneath of the sub.  Most reproduction units will say "Made in Korea" instead.

The 3820 flatcar can be found in good numbers. Ensure that the car has no chipped steps.  The hardest piece to find is an orginal 3830 submarine.

If a good specium is found - buy it immediately.