rail_data = {
    ["straight-rail"] = {
        [dir.north] = {
            length = 2,
            travel_to_rd = {
                [dir.north] = rd.front,
                [dir.south] = rd.back
            },
            rd_to_travel = {
                [rd.front] = dir.north,
                [rd.back] = dir.south
            },
            signals = {
                    [rd.front] = {
                        {x=1.5, y= 0.5, d=dir.south, stops=-1, starts=0},  -- Train stops 1 unit before this rail begins
                        {x=1.5, y=-0.5, d=dir.south, stops=1, starts=2}
                    },
                    [rd.back] = {
                        {x=-1.5, y=-0.5, d=dir.north, stops=-1, starts=0},
                        {x=-1.5, y= 0.5, d=dir.north, stops=1, starts=2},
                    },
            },
            next_rails = {
                [rd.front] = {
                    [rcd.left] = {type = "curved-rail", direction = dir.north, position = {x = -1, y = -5}},
                    [rcd.straight] = {type = "straight-rail", direction = dir.north, position = {x = 0, y = -2}},
                    [rcd.right] = {type = "curved-rail", direction = dir.northeast, position = {x = 1, y = -5}}
                },
                [rd.back] = {
                    [rcd.left] = {type = "curved-rail", direction = dir.south, position = {x = 1, y = 5}},
                    [rcd.straight] = {type = "straight-rail", direction = dir.north, position = {x = 0, y = 2}},
                    [rcd.right] = {type = "curved-rail", direction = dir.southwest, position = {x = -1, y = 5}}
                }
            },
        },
        [dir.northeast] = {
            length = sqrt2,
            travel_to_rd = {
                [dir.northwest] = rd.front,
                [dir.southeast] = rd.back
            },
            rd_to_travel = {
                [rd.front] = dir.northwest,
                [rd.back] = dir.southeast
            },
            signals = {
                [rd.front] = {{x=1.5, y=-1.5, d=dir.southeast, stops=-1, starts=1}},
                [rd.back] = {{x=-0.5, y=0.5, d=dir.northwest, stops=0, starts=1}},
            },
            next_rails = {
                [rd.front] = {
                    [rcd.left] = {type = "curved-rail", direction = dir.southeast, position = {x = -3, y = -3}},
                    [rcd.straight] = {type = "straight-rail", direction = dir.southwest, position = {x = 0, y = -2}},
                    [rcd.right] = nil--{type = "curved-rail", direction = dir.northeast, position = {x = 1, y = -5}}
                },
                [rd.back] = {
                    [rcd.left] = nil, --{type = "curved-rail", direction = dir.south, position = {x = 1, y = 5}},
                    [rcd.straight] = {type = "straight-rail", direction = dir.southwest, position = {x = 2, y = 0}},
                    [rcd.right] = {type = "curved-rail", direction = dir.north, position = {x = 3, y = 3}}
                }
            },
        },
    },
    ["curved-rail"] = {
        [dir.north] = {
            length = curve_length,
            travel_to_rd = {
                [dir.northwest] = rd.back,
                [dir.south] = rd.front
            },
            rd_to_travel = {
                [rd.front] = dir.south,
                [rd.back] = dir.northwest
            },
            signals = {
                [rd.front] = {
                    {x=-2.5, y=-1.5, d=dir.northwest, stops=-1, starts=0},
                    {x=-0.5, y=3.5, d=dir.north, stops=curve_length-1, starts=curve_length}
                },
                [rd.back] = {
                    {x=2.5, y=3.5, d=dir.south, stops=-1, starts=0},
                    {x=-0.5, y=-3.5, d=dir.southeast, stops=curve_length-1, starts=curve_length}
                },
            },
            next_rails = {
                [rd.front] = {
                    [rcd.left] = {type = "curved-rail", direction = dir.south, position = {x = 2, y = 8}},
                    [rcd.straight] = {type = "straight-rail", direction = dir.north, position = {x = 1, y = 5}},
                    [rcd.right] = {type = "curved-rail", direction = dir.southwest, position = {x = 0, y = 8}}
                },
                [rd.back] = {
                    [rcd.left] = nil, --{type = "curved-rail", direction = dir.south, position = {x = 1, y = 5}},
                    [rcd.straight] = {type = "straight-rail", direction = dir.northeast, position = {x = -3, y = -3}},
                    [rcd.right] = {type = "curved-rail", direction = dir.south, position = {x = -4, y = -6}}
                }
            },
        },
        [dir.northeast] = {
            length = curve_length,
            travel_to_rd = {
                [dir.northeast] = rd.back,
                [dir.south] = rd.front
            },
            rd_to_travel = {
                [rd.front] = dir.south,
                [rd.back] = dir.northeast
            },
            signals = {
                [rd.front] = {
                    {x=0.5, y=-3.5, d=dir.northeast, stops=-1, starts=0},
                    {x=-2.5, y=3.5, d=dir.north, stops=curve_length-1, starts=curve_length},
                },
                [rd.back] = {
                    {x=0.5, y=3.5, d=dir.south, stops=-1, starts=0},
                    {x=2.5, y=-1.5, d=dir.southwest, stops=curve_length-1, starts=curve_length},
                },
            },
            next_rails = {
                [rd.front] = {
                    [rcd.left] = {type = "curved-rail", direction = dir.south, position = {x = 0, y = 8}},
                    [rcd.straight] = {type = "straight-rail", direction = dir.north, position = {x = -1, y = 5}},
                    [rcd.right] = {type = "curved-rail", direction = dir.southwest, position = {x = -2, y = 8}}
                },
                [rd.back] = {
                    [rcd.left] = {type = "curved-rail", direction = dir.southwest, position = {x = 4, y = -6}},
                    [rcd.straight] = {type = "straight-rail", direction = dir.northwest, position = {x = 3, y = -3}},
                    [rcd.right] = nil
                }
            },
        },
    }
}