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Specialized Clamp, Handle and Connector Shunts

The C&T Shunts in this section are shunts with special-purpose connecting/clamping devices. They have been developed in response to customer need. Included in this section are our well-known Warren Fast Shunt, or “handle” shunt products, Probe-equipped and File Shunts.

506CB Clamp Bracket Head of Rail Shunt

Developed for a major railroad as a safety-related solution to using the gold nut switch with a bad back.  Others have chosen the CB Shunt to move the Resistor Bracket from the middle of the wire to a clamp end.  With the Clamp Bracket Shunt the
Resistor Bracket, which is normally in the middle of the shunt wire is cantilevered off the end of one of the head of rail clamps, leaving six feet of wire to the other head of rail clamp, unobstructed. Available in Head of Rail Clamp configuration only.  To order this shunt use 506CB prefix, replacing the 506 prefix.

506 Guard Rail Shunt

Clamps used with 506/550GR Series Commissioning and Testing Shunts are designed to accommodate the set-up, adjustment and testing of track circuits that are located in areas where guard rails are prevalent.  This situation is more common in transit systems where tracks are overhead on trestles or other elevated structures. Our 506/550GR Series Shunts come with special-design, S&C railroad grade, head-of-rail clamps.


Ordering Considerations:

  1. Specify whether you want one or two Guard Rail Clamps by replacing the * in the ordering references below with a 1 or 2, as appropriate.
  2. Specify resistances – see list above
  3. Specify color by replacing the X in the ordering references below with a B, O, R or Y (Black, Orange, Red or Yellow)
  4. If high in-rush resistors are required change the “506” portion of the below references to “550”

1Guard Rail Shunt, Zero Ohm506GR(*)-00(X)
2Guard Rail Shunt, Single Resistance and Zero506GR(*)-(_ _)(X)
3Guard Rail Shunt, Two Resistance and Zero506GR(*)-(_ _) (_ _)(X)
4Guard Rail Shunt, Three Resistance and Zero506GR(*)-(_ _)-(_ _)-(_ _)(X)
5Guard Rail Shunt, Four Resistance and Zero506GR(*)-(_ _)-(_ _)-(_ _)-(_ _)(X)
6Guard Rail Shunt, Five Resistance and Zero506GR(*)-(_ _)-(_ _)-(_ _)-(_ _)-(_ _)(X)
7Guard Rail Shunt, w/Track Circuit Calibrator Configuration – Ten Resistances and Zero506GRMS-(When ordering, list 10 or fewer resistances required)
506 Web-Of-Rail Clamp Shunt

Developed as a substitute for a standard head-of-rail clamp shunt to address heavily lipped-over rail or head-free rail, particularly where the ballast is solidly frozen. These Web-of-Rail Clamps encompass the entire rail head with or without heavy lip, causing the Connector and T-screw to connect the rail at the web.  Due to the distance covered, the Clamps are necessarily large, weighing X pounds each and the T-Screws over-sized in both diameter and length.

Select resistance value or values:  .06, .07, .10, .12,.15, .18, .20, .25, .30, .40, .50, 1.00, 1.10, 1.20, 1.30, 1.40, 1.50 and 2.0.  Use “15X” for 1.50 ohm value and “2X” for 2.0 ohm value.  Up to five resistances can be included in one Resistor Bracket.  All test nuts down equals Zero ohm resistance.

Black Wire Is furnished unless requested otherwise.  Other choices are Red, Safety Orange and Brite Yellow.  Add Z to indicate Heavy Duty Shunt Carry Bag

506AFI Imbedded Rail Shunts

Adjustment and testing of track  circuits  that operate in an imbedded, (Photos) or flush rail environment are difficult if not impossible with conventional clamp type shunts.  File or Probe Shunts, while effective for quick tests of such track circuits, should never be used  for adjustment purposes. S&C Distribution Company offers commissioning and testing shunts equipped with easy-to-use, specialized clamps for use in imbedded track.

Whether the flangeway is created with plastic, rubber, metal, concrete or macadam, the 506AF  Series lmbedded Rail Testing Shunts provide a very effective means of applying firm electrical connections to the rail. Accurate and reliable adjustments to, and testing of, track circuits working in such  environments are readily achieved.

A key feature of the 506AFI Shunt is its ability to accommodate various flangeway  configurations in addition to those that are components of traditional Girder or Trilby rail. More recent flangeways vary from the traditional in depth and width.  The 506AFI Shunt can  adjust to these changes in two ways; the depth of penetration into the flangeway and the amount of width of the flangeway accommodated.  See photos accompanying this section for details.

Penetration into the flangeway is controlled by the Support Brackets that are bolted to the outside edges of both Clamps.  Support Brackets are intended to bridge the flangeway and hold the Clamp at a height so that the Clamp will reliably contact the head of one of the rails of the track to be shunted.  Where needed, firm contact with the rail head is assured by Blocking Bolts that extend to the rear of the Clamp to engage the roadway edge of the flangeway.  A matching Clamp connects, in similar fashion, to the other rail completing the shunting of the track circuit.

Unique design of the connectors and shunt wires assures extremely low probability of  resistance variations within the shunt. Resistance values are switchable between common testing  values and zero ohms with test nuts. A gold nut-operated OPEN can be included in the Resistor Bracket Sub-Assembly to allow the Shunt to be temporarily opened without  removing a clamp from the rail.  For the large variety of resistance values available, see the “Specifying Resistance Values” section of this brochure.

Clamps include handles for portability.  Heavy-duty Carry Bags are  included with the Shunts.


 DescriptionPart Number
Zero Ohm, Hardwire Shunt506AFi-00
Single Resistance & Hardwire Shunt506AFI-(  _)
Dual Resistance & Hardwire Shunt or Single Resistance, Hardwire and Open506AFI-(  _) (__)


506 Warren Fast Shunts

Several years ago, a customer came to us with a request for a shunt that (506WFS)    would be quick to apply and reliable for circuit activation testing.  The result is our Warren Fast Shunt in handle lengths of 14, 24 and 38 inches, for those who “do not want to bend over at all”.  The 14 inch handle version is shown in the photo.  Handle lengths limit the number of resistances that can be accommodated.  These products have become standards across North America.  They are available in every resistance combination, and shunts with all length handles can come equipped with heavy-duty, protective Shunt Bags.  A version, with built-in, limited, AC & DC analog meter, with either 24 or 38 inch handles is also available for use in doing shunt-fouling tests.

(Insert resistance value or values .06, .07, .10, .12, .15, .18, .20, .25, .30, .40, .50, 1.00, 1.10, 1.20, 1.30, 1.40, 1.50 and 2.0, where blanks in parenthesis are shown, omitting decimal. Examples:  use  “15X” for 1.5 Ohm value and “2X” for 2.0 ohm value.)  Note that the 38 inch handle shunt can accommodate resistance counts beyond five, to and including the ten resistance and zero Multi-Shunt configuration.

Shunt with 14 Inch Handles 
Hardwire Shunt506WFS-00
Single Resistance and Zero506WFS-(_ _)
2 Resistances and Zero506WFS-(_ _) (_ _)
Shunt With 24 Inch Handles 
Single Resistance & Zero506WFS24-(_ _)
2 Resistances & Zero506WFS24-(_ _) (_ _)
3 Resistances & Zero506WFS24-(_ _) (_ _) (_ _)
4 Resistances & Zero506WFS24-(_ _) (_ _) (_ _) (_ _)
AC-Only Shunt506WFS24-AC
Shunt With 38 Inch Handles 
Hardwire Shunt506WFS38-00
Single Resistance & Zero506WFS38-(_ _)
2 Resistances & Zero506WFS38-(_ _) (_ _)
3 Resistances & Zero506WFS38-(_ _) (_ _) (_ _)
4 Resistances & Zero506WFS38-(_ _) (_ _) (_ _) (_ _)
5 Resistances & Zero506WFS38-(_ _) (_ _) (_ _) (_ _) (_ _)
Multiple (10) Resistance Shunt & Zero506WFS38-MS1
AC-Only Shunt506WFS38-AC
Shunt Bags For Above 
Bag for 14 Inch Handle Shunt506ONBZB
Bag for 24 Inch Handle Shunt506ONBZB-24
Bag for 38 Inch Handle Shunt506ONBZB-38

Typical Ordering Reference for a 2-Resistance (plus Zero) Shunt, Black Wire, with Carry Bag: 506W-(_ _)(_ _)BZ  

For Example:  506W-(06)-(25)BZ

Additional resistances would be indicated by additional values in parenthesis, in series with those shown above.  Note that the numbering of the “official” part number may vary slightly from the sequence you provide us.

506 Probe and Bracket Probe Shunts

A new way to connect testing shunts to the rail temporarily and easily.  506P and 506BP Shunts utilize the probe concept, providing railroad-durable steel, 12.5 inch Probes (including the handle length) with tips that are file-hard.  The 12 inch length makes reaching rail to rail with enough leverage to effect a reliable shunt, doable. The hardened tips insure long service life.  Probes are hard-tool chromed after fabrication and heat-treating, for resistance to rust, etc.  Our Probe shunts are especially helpful in making “rolling” shunt, crossing operation verification and shunt fouling, tests.  Probe Shunts come in several resistance configurations:  Zero Ohm (hardwire), switchable with test nut between zero ohm and one or two testing resistances of your choice; and in an AC-Only configuration for specialized crossing warning system activation testing applications.

(Insert resistance value or values:  .06, .07, .10, .12, .15, .18, .20, .25, .30, .40, .50, 1.00, 1.10, 1.20, 1.30, 1.40, 1.50 and 2.0 ohms) where  blanks  in  parenthesis  are  shown, omitting  decimal. Use “2X” for two ohm value)

AProbe Shunt, Single Resistance and Zero506P-(__)
BProbe Shunt, Dual Resistance and Zero506P-(_ _) (_ _)
A1Bracket Probe Shunt, Single Resistance and Zero506BP-(_ _)
B1Bracket Probe Shunt, Dual Resistance and Zero506BP-(_ _) (_ _)
RAHandle, w/Probe506P-1
RBProbes, only, 1 Pair506P-2
RCProbe Shunt Wire, Single Resistance and Zero506-(_ _)-1
RDProbe Shunt Wire, Dual Resistance and Zero506-(_ _) (_ _)-1
RC1Bracket Probe Shunt Wire, Single Resistance and Zero506BP-(_ _)-1
RD1Bracket Probe Shunt Wire, Dual Resistance and Zero506BP-(_ _) (_ _)-1
506 File and Bracket File Shunts

(It should be noted that modern rail is made from a steel that is high in chrome and molybdenum.  This makes the rail more brittle than it was in carbon steel days.  The result is that files can damage the rail to the point where it wil  breakOur use of round files makes notching the rail more difficult but not impossible. Exercise great care when using File Shunts or consider our Probe Shunts, listed above)  

A new variation on an old way to connect testing shunts to the rail temporarily and easily.  506 and 506B Shunts utilize round metal files, providing 16 inch reach (including the handle length). The 16 inch length makes reaching rail to rail with enough leverage to effect a reliable shunt, doable.  Our File shunts can be helpful in making “rolling” shunt, crossing operation verification and shunt fouling, tests.  File Shunts come in several resistance configurations:  Zero Ohm (hardwire), switchable with test nut between zero ohm and one or two testing resistances of your choice; and in an AC-Only configuration for specialized crossing warning system activation testing applications.