Apparatus and Method For Monitoring Railroad Track For Buckling Risk

Apparatus for monitoring longitudinal strain in a railroad rail and determining a location along the rail where there is a significant risk of buckling, comprising:

• a length of fiber optic cable secured to a side of the rail, said cable including a series of longitudinally spaced optical backscatter creating discontinuities;
• signal transmitting and receiving means operatively associated with said cable for determining changes in the distances between the discontinuities;
• threshold setting means for setting a rail temperature dependent threshold distance change between discontinuities, which threshold distance change corresponds to a minimum acceptable level of change in longitudinal rail strain;
• warning means coupled to said signal transmitting and receiving means and said threshold setting means for generating a buckling risk warning signal when the distance change between the discontinuities at a buckling risk location along the rail falls below the minimum threshold distance change set by said threshold setting means;
• and
• buckling risk location determining means operatively associated with said warning means for determining and displaying said buckling risk location, by determining the transit time of an optical signal between the buckling risk location and the buckling risk location determining means.

Apparatus for monitoring longitudinal strain in a railroad rail and determining a location along the rail where there is a significant risk of rail fracture due to contraction stress at low temperature, comprising:

• a length of fiber optic cable secured to a side of the rail, said cable including a series of longitudinally spaced optical backscatter creating discontinuities;
• optical signal transmitting, receiving and data processing means operatively associated with said cable for determining decreases in the cable strain between said discontinuities;
• threshold setting means for setting a rail temperature dependent threshold strain change parameter corresponding to a minimum acceptable level of low temperature longitudinal rail strain change between said discontinuities;
• warning means coupled to said optical signal transmitting, receiving and data processing means and said threshold setting means for generating a fracture risk warning signal when the cable strain change at a low temperature fracture risk location adjacent one or more of said discontinuities falls below the parameter set by said threshold setting means,
• whereby said warning signal is generated when an unacceptably low amount of strain change occurs;
• and
• fracture risk location means operatively associated with said warning means for determining and displaying said fracture risk location.

A process for monitoring longitudinal strain in a railroad rail and determining a location along the rail where there is a significant risk of buckling, comprising the steps of:

• affixing a length of fiber optic cable to a side of the rail, said cable including a series of longitudinally spaced optical backscatter creating discontinuities;
• transmitting an optical signal through said cable from a light source, said discontinuities causing backscatter of said signal;
• receiving and data processing the backscatter containing optical signal to determine changes in the cable strain between said discontinuities;
• setting a rail temperature dependent threshold strain change parameter corresponding to a minimum acceptable level of longitudinal rail strain change between said discontinuities;
• generating a buckling risk warning signal when the cable strain change at a buckling risk location adjacent one or more of said discontinuities falls below said parameter;
• and
• determining the buckling risk location by measuring the optical signal transit time between a known location and the location at which the cable strain change falls below said parameter.

Apparatus for monitoring longitudinal strain in a multi-strand support cable under tension and determining when there is a significant likelihood that at least one cable strand has broken, comprising:

• a length of fiber optic cable secured to the support cable, said fiber optic cable including two or more longitudinally spaced optical backscatter creating discontinuities;
• optical signal transmitting, receiving and data processing means, including a light source, operatively associated with said fiber optic cable for determining changes in the cable strain between said light source and at least one of said discontinuities by measuring the round trip transit time between said signal transmitting, receiving and data processing means and said at least one discontinuity;
• threshold setting means for setting a threshold strain change parameter corresponding to a maximum acceptable level of longitudinal support cable strain change between said signal transmitting, receiving and data processing means and said at least one discontinuity;
• and
• warning means coupled to said optical signal transmitting, receiving and data processing means and said threshold setting means for generating a support cable strand breakage warning signal when the cable strain change between said signal transmitting, receiving and data processing means and said at least one discontinuity exceeds the parameter set by said threshold setting means,
• whereby said warning signal is generated when there is likely to be a breakage of said strand.

Apparatus for monitoring longitudinal strain in an enclosed vessel under internal or external pressure, said vessel having a surrounding hull or casing, and determining when there is a significant likelihood of collapse of said hull or casing due to such pressure, comprising:

• a length of fiber optic cable secured to the hull or casing, said fiber optic cable including two or more longitudinally spaced optical backscatter creating discontinuities;
• optical signal transmitting, receiving and data processing means, including a light source, operatively associated with said fiber optic cable for determining changes in the cable strain between said light source and at least one of said discontinuities by measuring the transit time between said signal transmitting, receiving and data processing means and said at least one discontinuity;
• threshold setting means for setting a threshold strain change parameter corresponding to a maximum acceptable level of hull or casing strain change between said signal transmitting, receiving and data processing means and said at least one discontinuity;
• and
• warning means coupled to said optical signal transmitting, receiving and data processing means and said threshold setting means for generating a hull or casing warning signal when the cable strain change between said signal transmitting, receiving and data processing means and said at least one discontinuity exceeds the parameter set by said threshold setting means,
• whereby said warning signal is generated when there is likely to be a collapse of said hull or casing.