Sand level monitoring system

1. A system for monitoring a sand reservoir comprising:

a sand reservoir carried on an off-highway vehicle;

a sand level indicator coupled to the sand reservoir, the sand level indicator comprising a display device disposed external to the sand reservoir and configured to provide a visual display indicative of a quantity of sand within the sand reservoir, the sand level indicator comprising:

(a) an elongated inner member positioned inside the sand reservoir, an outer surface of the inner member being conductive substantially throughout the length thereof;

(b) a resilient elongated outer member surrounding the inner member, an inner surface of the outer member being conductive substantially throughout the length thereof;

(c) an electrical circuit connected across the inner and outer members;

(d) the inner and outer members being disposed within the sand reservoir so that the lengths thereof extend substantially through a height of the sand reservoir to span a range of sand levels within the sand reservoir for indicating a quantity of sand stored in the reservoir based on a height of the sand stored in the sand reservoir, the inner and outer members being arranged such that compression of the outer member against the inner member by sand causes a change in a resistance of the circuit; and

(e) a display positioned external to the sand reservoir which displays a sand level within the tank based on the resistance.

2. The system of claim 1 wherein the at least one sand level indicator comprises: a first sand level indicator having a visual display visible outside a body of the vehicle; and a second sand level indicator having a visual display visible inside the body of the vehicle.

3. A system for monitoring a sand reservoir of an off-highway vehicle, comprising:

(a) an off-highway vehicle unit carrying a sand reservoir;

(b) a sand level indicator comprising:

(i) an elongated inner member positioned inside the sand reservoir;

(ii) a resilient elongated outer member surrounding the inner member; and

(iii) an electrical circuit connected across the inner and outer member;

(iv) wherein the inner and outer members are positioned to span a range of sand levels within the sand reservoir, and arranged such that compression of the outer member against the inner member by sand causes a change in a resistance of the circuit; and

(v) a device operatively coupled to the electrical circuit which is operable to determine a sand level within the tank based on the resistance;

(c) a transmitter coupled to the sand level indicator; and

(d) a remote station having a receiver in communication with the transmitter for receiving the signal.

4. The system of claim 3 wherein the at least one sensor and the transmitter are coupled to a central processing unit located on-board the off-highway vehicle.

5. A system for monitoring a sand reservoir of a locomotive comprising:

a sand reservoir mountable to a locomotive for carrying sand;

a sand level indicator carried by the sand reservoir, the sand level indicator comprising:

(a) an elongated inner member positioned inside the sand reservoir, an outer surface of the inner member being conductive substantially throughout the length thereof;

(b) a resilient elongated outer member surrounding the inner member, an inner surface of the outer member being conductive substantially throughout the length thereof;

(c) an electrical circuit connected across the inner and outer members;

(d) the inner and outer members being disposed within the sand reservoir so that the lengths thereof extend substantially through a height of the sand reservoir to span a range of sand levels within the sand reservoir for indicating a quantity of sand stored in the reservoir based on a height of the sand stored in the sand reservoir, the inner and outer members being arranged such that compression of the outer member against the inner member by sand causes a change in a resistance of the circuit;

a processor in communication with the circuit, the processor configured to, based on the resistance, generate data corresponding to the quantity of sand for transfer to a remote location; and

a transmitter coupled to the processor and configured to transmit the data to a remote location.

6. The system of claim 5 further comprising a remote station having a receiver in communication with the transmitter for receiving the data.

7. A system for monitoring a sand reservoir of an off-highway vehicle comprising:

an off-highway vehicle;

a sand reservoir mounted to the off-highway vehicle for carrying sand;

a sand level indicator carried by the sand reservoir, the sand level indicator comprising:

(a) an elongated inner member positioned inside the sand reservoir, an outer surface of the inner member being conductive substantially throughout the length thereof;

(b) a resilient elongated outer member surrounding the inner member, an inner surface of the outer member being conductive substantially throughout the length thereof;

(c) an electrical circuit connected across the inner and outer members;

(d) the inner and outer members being disposed within the sand reservoir so that the lengths thereof extend substantially through a height of the sand reservoir to span a range of sand levels within the sand reservoir for indicating a quantity of sand stored in the reservoir based on a height of the sand stored in the sand reservoir, the inner and outer members being arranged such that compression of the outer member against the inner member by sand causes a change in a resistance of the circuit;

a processor onboard the off-highway vehicle and in communication with the circuit, the processor configured to, based on the resistance, generate data corresponding to the quantity of sand for transfer to a remote location; and

a transmitter coupled to the processor and configured to transmit the data to a remote location.

8. The system of claim 7 further comprising a remote station having a receiver in communication with the transmitter for receiving the data.

9. A sensor for determining an amount of sand in a sand reservoir, comprising:

an elongated inner member adapted to be positioned inside a sand reservoir, an outer surface of the inner member being conductive substantially throughout the length thereof;

a resilient elongated outer member surrounding the inner member, an inner surface of the outer member being conductive substantially throughout the length thereof; and

an electrical circuit connected across the inner and outer member;

wherein the inner and outer are arranged such that a magnitude of a resistance of the electrical circuit will vary in response to compression of the outer member against the inner member by sand.