SWITCHES & CROSSINGS

• Commonly known as S&C
• Defined as track components that exist to provide a means whereby trains may be directed from one track or route to another track or route.
• Consist of: one (or more) sets of switches

         common (or acute) crossing and (sometimes) obtuse crossings   

 TURNOUTS  

COMMON (or ACUTE) CROSSING – where ‘turnout’ rail and ‘through’ rail intersect.

SWITCHES (or points) – where divergence between alternative routes begin.

DIAMOND CROSSINGS

* 2 x COMMON CROSSINGS

* 2 x OBTUSE CROSSINGS

SLIP DIAMOND CROSSINGS

SETS OF SWITCHES WITHIN THE DIAMOND TO ALLOW TRAINS TO ACCESS ADDITIONAL PATHWAYS.

SLIP DIAMONDS CAN BE OF A SINGLE OR DOUBLE VARIETY.

DESCRIPTION

• Denoted by LETTER to indicate planing
• V after letter indicates a VERTICAL configuration
• Types: A … 2.9m PLANING LENGTH

                  B … 3.5m

                  C … 4.25m

                  D … 5.2m

                  E …  7.0m

                  F …  8.55m

                  G … 11.6m

                  H … 17.495m

GRAPHITE LUBRICANT INSERTS IN A COPPER-TIN ALLOY MATRIX (Hence the CuSn prefix)

Mandatory requirement at switch toe to tie the stock rails to the req’d gauge. Gauge stops are welded to locate the slide baseplate

NOTE : SHALLOW-DEPTH SWITCHES

COMMON CROSSINGS (BUILT-UP UNITS) COMPRISE:

DESCRIPTION:

DENOTED BY CROSSING ANGLE  i.e. 1 in xx

COMMON ANGLES IN USE :

                            1 in  8

                            1 in  91/4

                            1 in  10

                            1 in  103/4

                            1 in  131/4

                            1 in  15

                            1 in  18

                            1 in  21

                            1 in  24

                            1 in  28

                            1 in  32

DESIGN OF SWITCHES & CROSSINGS

NR60 S&C

• Flat bottom, inclined shallow depth designs of S&C

• Designed for use in tracks carrying high speeds or heavy tonnages

• Units are strengthened for use with C.W.R.

• NR60 C-8.25 turnout with concrete bearers

Note that TWO back-drives are fitted with the shallow depth switches

NR60 S&C with ‘TORSION’ type drive bar (down centre of fourfoot)

This system is a variation of the drive system shown on the preceding slide

NR60 transition rail

Provided at the back of the switches to allow transfer from E1 to 113A rail sections

Note the ‘piggy back’ fastening pad to provide connection for the shallower-depth rail.

BALL and CLAW

Fitted to any NR60 layout using switches SHARPER than an F design

Minimises longitudinal creep of the switch rails and provides a useful ‘tell-tail’ for monitoring the position of the switches.

Note : the ball and claw does NOT provide for any stress transference between switch and stock rails. 

33 C 1 CHECK RAILS

Continental style check rails

Are being increasingly used in S&C layouts

The design enabled the full width of the 113a rail foot to be retained for increased stability.

33 C 1 Check rail bracket baseplate

33 C 1 Check rail bracket baseplate

The design allows for the insertion of shims between the vertical face of the back of he check to compensate for wear on the rubbing face of the check.

NR60  1 in 13.5 SWING NOSE CROSSING

Comprises an electro-slag welded moveable nose within 60 E 1 wing rails

Note the use of hollow steel bearers at the nose and heel of the crossing.

NR60  1 in 13.5 SWING NOSE CROSSING   HEEL FLEXING JOINT

A mitred joint to allow for the movement of the crossing