Slide Gate, Slide Gate Operators, or Slide Gate Openers
Typically use a chain to open the gates, some security models use a type of angle track so the chain could not be cut therefore creating higher security features.
Slide gate operators are used when there is limited space behind a secured facility, so the gate must run parallel to  a fence or wall.

• Can be used as single or bi-parting gates
• V-track / V-groove or Cantilever
• Standard or custom design

Now lets explain some terms here:

• V-track / V-groove
  v-groove / v-track is typically a piece of angle metal mounted in the ground to allow the slide gates v-groove wheels to slide along the track.
  
  
• Cantilever
  A cantilever slide gate is supported on a gate post and on a line post spaced from the fence post on the side opposite the gate opening by means of a pair of brackets, one secured to each post.Each bracket supports a pair of fixed rollers with their axes horizontal in a transverse vertical plane normal to a longitudinal vertical plane through the post. A longitudinally movable track is supported on the rollers by means of two spaced apart top flanges. The track also has two spaced apart bottom flanges which support the gate by means of two pairs of spaced apart rollers secured to the top of the gate with their axes parallel to the axes of the fixed rollers, these rollers resting on the bottom flanges. One pair of the gate rollers is positioned generally centrally of the gate and the other pair is positioned on the side toward the line post. Means are provided to cause the track and gate to move in unison with the gate movement being twice that of the track movement.
  
• Bi-parting
  Two gates working together as one that meet in the middle of the opening.