LSL Guide

integer wolfCouplerSetPoint(string name, vector localPos)

Name a hitch point on this object, in its root prim's frame (+X forward, +Y left, +Z up), for a rear object to couple to. Up to 8 points; setting a name again moves it.

Names a hitch point on this object for a rear object to couple to: a fifth wheel, a tow ball, a coupler hook. The position is in the ROOT prim's frame (+X forward, +Y left, +Z up — the vehicle frame), wherever in the linkset the script is. An object can have up to 8 points; setting a name again moves that point. Each point takes one rear. Returns 1, or 0 with wolfGetLastError saying why.

Parameters

// A locomotive with couplers at both ends.
default
{
    state_entry()
    {
        wolfCouplerSetKey("wolfrail");
        wolfCouplerSetPoint("rear",  <-7.2, 0.0, 0.6>);
        wolfCouplerSetPoint("front", < 7.2, 0.0, 0.6>);
    }
}

touch_start(integer n) { llOwnerSay((string)((llDetectedTouchPos(0) - llGetRootPosition()) / llGetRootRotation())); }

Ours alone. Grid features you will not find on any other OpenSimulator grid.