Active spark control

1. A method for directing a spark stream generated by contact between a rotating grinding stone and a railhead away from nearby combustible material, said method comprising tilting said grinding stone at an angle such that only one of a leading edge and a trailing edge of said grinding stone contacts said railhead surface, said tilting provided in a plane defined by a longitudinal axis of said railhead and an axis of rotation of said grinding stone.

2. The method of claim 1 further comprising tilting said grinding stone such that said one of said leading and trailing edges which contacts said railhead results in said spark stream being directed upwardly and away from said nearby combustible material.

3. The method of claim 1 further comprising tilting said grinding stone as a function of a direction of rotation of said grinding stone and whether said grinding stone contacts said railhead on a gauge side or on a field side of said railhead.

4. The method of claim 3 further comprising:

a. said direction of rotation of said grinding stone is clockwise;

b. said leading edge selected to contact said railhead when said grinding stone is operated at a grinding angle of more than (+) 15 degrees as defined in accord with conventional rail grinding patterns;

c. said trailing edge selected to contact said railhead when said grinding stone is operated at a grinding angle (+) 15 degrees or less as defined in accord with conventional rail grinding patterns.

5. The method of claim 1 further comprising tilting said grinding stone at an angle of from about 0.31 to about 0.81 degrees from horizontal.

6. The method of claim 1 wherein said angle is about 0.56 degrees.

7. An apparatus for grinding a railhead comprising:

a. a grinding unit having a rotatable grinding stone, said grinding stone having a leading edge and a trailing edge;

b. a support member adapted to hold said grinding unit in a position with said grinding stone against said railhead during a grinding operation;

c. a tilting assembly associated with said support member and said grinding unit, said tilting assembly controllable to tilt said grinding unit in a plane defined by an axis of rotation of said grinding stone and a longitudinal axis of said railhead;

d. wherein said grinding stone is held at an angle against said railhead during said grinding operation such that only one of said leading and trailing edges contacts said railhead during said grinding operation; and

e. wherein said one of said leading and trailing edges is selected such that a spark stream generated by said grinding operation is directed away from nearby combustible material.

8. The apparatus of claim 7 wherein said tilting assembly further comprises:

a. a tilt bracket connected to said grinding unit via upper and lower pairs of parallel arms;

b. said upper pair of parallel arms connected between an upper portion of said tilt bracket and an upper part of said grinding unit;

c. said lower pair of parallel arms connected between a lower portion of said tilt bracket and a lower part of said grinding unit adjacent said grinding stone; and

d. said upper pair of parallel arms connected to said tilt bracket via an eccentric assembly wherein rotation of said eccentric assembly shortens or lengthens said upper pair of parallel arms relative to said lower pair of parallel arms such that said grinding unit, and thus said grinding stone, is tilted relative to said railhead.

9. The apparatus of claim 8 wherein said eccentric assembly further comprises:

a. a shaft connected between said upper pair of parallel arms;

b. a hollow tubular member disposed over said shaft for rotation relative thereto, said upper portion of said tilt bracket carried by said hollow tubular member, said hollow tubular member having an inner axis coaxial with said shaft and an outer axis eccentric to said inner axis such that rotation of said hollow tubular member relative to said shaft shortens or lengthens said upper pair of parallel arms relative to said lower pair of parallel arms; and

c. an actuator connected to said hollow tubular member for rotating said hollow tubular member relative to said shaft to tilt said grinding stone relative to said railhead to direct said spark stream away from said nearby combustible materials.

10. The apparatus of claim 9 further comprising:

a. said actuator being a variable length member having a fixed end and a second end movable toward said fixed end;

b. said hollow tubular member having a lever extending therefrom, said lever connected to said second end of said variable length member; and

c. wherein movement of said second end of said variable length member toward said first end thereof rotates said hollow tubular member relative to said shaft to shorten or lengthen said upper pair of parallel arms relative to said lower pair of parallel arms to tilt said grinding stone relative to said railhead.

11. The apparatus of claim 7 wherein said angle is from about 0.31 to about 0.81 from horizontal.

12. The apparatus of claim 11 wherein said angle is about 0.56 degrees.