Electric flat cars, also known as electric flatbed trucks, electric level cars, trolleys, undercrossing vehicles, electric track cars, and ground-crawling vehicles, are a type of on-site electric track transport vehicle within factories. Firstly, they are track-type transport vehicles that require tracks to be laid on the ground, typically with I-beam-shaped surfaces for contact with the tracks. Secondly, they are electric-powered vehicles that operate automatically under the drive of electric motors and reducers. Additionally, they are flatbed vehicles with a level surface and no box cover; in special cases, they can be non-planar but still without a box cover. The vehicle body lacks a steering wheel, operating only in forward and reverse directions (even when turning, it relies on the track for the turn). This type of vehicle features simple structure, ease of use, high load-bearing capacity, resistance to dirt and damage, easy maintenance, and a long service life. Due to its convenience, robustness, economy, practicality, and ease of cleaning, it has become a transportation tool for frequently transporting heavy loads over short distances within and between factory buildings.

Electric trolleys are mainly used in mobile lifting water transport vehicles, etc.; in brickworks, kiln factories, refractory factories, ceramics factories, and calcining factories for electric kiln loading and unloading carts, etc.; in engineering, tunnels, and environmental sanitation for electric transport vehicles, electric dump trucks, and electric waste collection vehicles, etc. Electric transport and dump trucks are also used in flour mills, mining processing plants, foundries, chemical factories, furnace material factories, and farms, etc.