Here is a Lionel 6-8111 O Gauge DT&I NW-2 Switcher Diesel Locomotive from 1971-74. 

When bench tested, it ran well both forward and back using the simple direction lever up on top of the engines main body hood.  Note, This engines "E-unit" directional control seems to a simple, 2 directional (F or R) with no neutral, N .  The direction is set manually with the level.  This design is as it was made from/by Lionel.  Basically, it came this way.  

I'm told the motor can also run well using DC too, so you'd then have a remote direction control possibility.  This needs to be verified before using DC on it.  The good thing is there is No buzzing from a more traditional e-unit. There is just quiet running in either direction.

Features include 

Single motor  (it would not hurt to give it some fresh grease or oil and check it out before running it too much)

Traction tires on 2 of the drive wheels

Durable plastic construction,

A decorative bell, 

fixed couplers on both ends,

I don't know if it has a light inside or if its possibly burned out as I did not see any (working) light when it was tested.

1 die-cast metal truck with the drive (powered) wheels

1 plastic truck for the other wheels

and metal wheels and exquisite molded body detail.

The metal chassis has rust on it, shown 

This locomotive measures about 12 1/4". long.

It will come in a portion of the the set box it came in, which is dirty and may be best mostly for shipping it  more safely in.

Sold as shown