The track structure is the combination of the formation, ballast, drainage, sleepers, fastenings and rails.
Figure 48 – The Track
C4-1 Ballast
Ballast is the material placed between the capping layer and the sleepers. It is a free draining course aggregate.
Its purpose is to lock the sleepers in position and to spread the load from the sleepers to the formation.
1. There must be at least 270mm for timber (300mm for concrete) of ballast between the sleepers and the formation.
2. The ballast must be level with the top of the sleepers (this is called “crib”).
3. There should be at least 400mm of ballast at the end of each sleeper on main line track (this is called the “shoulder”).
4. The sides of the ballast must slope at an angle of 1:1.5 (this is called the batter angle).
Sleeper
Rails
Sleeper fastenings Dogspikes Lockspikes
Sleeper plates Anchors
Ballast
Figure 49 - Ballast profile
Figure 50 - Ballast profile
C4-2 Sleepers
Sleepers or “ties” are a very important part of the track structure. They are used to support the rails and keep them at the correct gauge (ie distance apart) and to transfer the loads from the rails to the ballast.
C4-2.1 Types of sleepers
Three types of sleepers are used in Australian railways - timber, concrete and steel. In RailCorp only timber and concrete sleepers are used.
Ballast Crib Ballast
Shoulder
Ballast level with top of timber sleeper Ballast slightly above lower centre of some concrete sleepers
Ballast shoulder width
Batter angle
1.5 1
Ballast toe
Figure 51 – Timber dogspiked track
Figure 52 – Concrete sleepered track
C4-2.2 Timber sleepers
Timber sleepers are in common use in RailCorp but are being replaced by concrete sleepers.
The timber in sleepers is hardwood and includes grey and red ironbark, White and grey box, Grey gum and River red gum species.
Sleeper
Anchor Sleeper plate
Lockspike
Dogspike
Insulator Cast-in Shoulder
Sleeper
Elastic fastening
C4-2.3 Timber half sleepers
Timber half sleepers are used in some areas of the City Underground and eastern Suburbs railway. They are secured directly to the concrete slab. Rail is attached with sleeper plates and fastenings. Some timber half sleepers in the City Underground have been replaced by polymer concrete half sleepers.
Figure 54 – Timber half sleepers
C4-2.4 Concrete sleepers
Concrete sleepers are preferred for use in RailCorp. They are progressively replacing timber sleepers because of:
• Decreasing availability of timber
• longer life span
• a more stable track due to greater weight and size
• price is comparable to timber at the stage where they go under the track (putting them in is more expensive as it is usually fully mechanised)
Figure 55 – Concrete sleepers
Concrete sleepers used in RailCorp are monoblock (cast in one piece) prestressed concrete (the reinforcing tendons are stressed before casting the concrete). They have cast in shoulders to hold the resilient fastenings.
There are two types of concrete sleeper used in RailCorp:
1. Medium duty (also known as low profile). Suitable for use in most applications for axle loads up to 25 tonne. They are approximately the same dimensions as timber sleepers and have been used in some locations mixed with timber sleepers.
Cast-in Shoulder Rail seat sloped at 1 in 20
2. Heavy duty. Used where heavy axle loads operate. They are deeper than timber or medium duty concrete sleepers and track generally needs to be lowered under overhead wiring to fit them in.
C4-3 Concrete slab track
In some locations track is laid directly on a concrete track bed. The rail fastenings are embedded in the slab.
Figure 56 – Concrete slab track
C4-4 Sleeper plates
Sleeper plates are attached to timber sleepers to provide a seat for the rail and to keep the rail leaning in towards the track centre at an angle of 1:20.
Because the plates have raised shoulders that engage the foot of the rail they also help to maintain the gauge by sharing the lateral load to the lockspikes.
There are three types of sleeper plate used in RailCorp on plain track.
Double shouldered plates which use lock spikes or lockscrews to hold the plate on the sleeper, dogspikes or dogscrews to hold the rail in the plate (and in the sleeper) and anchors to reduce rail creep. (See Figure 57).
Figure 57 - Double shouldered sleeper plate – used with dogspikes and lockspikes or dogscrews and lockscrews
Dogspike
Lockspike
Rail seat sloped at 1 in 20
Double shouldered plates which use lock spikes to hold the plate on the sleeper and elastic fastenings (clips) to hold the rail in the plate. (See Figure 58) The clips also reduce rail creep.
Figure 58 - Double shouldered sleeper plate – used with elastic fastenings and lockspikes Double shouldered plates which use screwspikes to hold the plate on the sleeper and elastic fastenings (clips) to hold the rail in the plate. (See Figure 59)
Figure 59 - Double shouldered sleeper plate with screw spikes
Concrete sleepers do not use sleeper plates. They are manufactured with cant at the rail seat and have attachments for the fastening systems built into the sleeper. (See Figure 55).
Around turnouts some plates are either “cant reducing” or “zero cant”(flat). The rails through turnouts are not sloped inwards at 1 in 20. They stand vertical. This means that the rail either side of the turnout must be gradually changed from 1 in 20 cant to flat. This is done with “cant reducing plates over a number of sleepers.
C4-5 Resilient baseplates
In locations where the noise and vibration generated by rail traffic needs to be reduced, resilient baseplates can be used. They are also called vibration isolation fastenings.
There are a number of products in use and you may hear them referred to as “Cologne eggs” or “Alternative 1”.
Figure 60 – Cologne eggs being installed
Figure 61 – Alternative 1 being installed
Generally they consist of two baseplates with rubber (or rubber like) material bonded in between. The bottom plate is fastened to the sleeper or directly to a concrete slab.
Standard resilient fastenings attach the top plate to the rail.
C4-6 Sleeper fastenings
Rails have to be securely fastened to the sleepers to ensure maintenance of correct gauge. To this end we use a variety of sleeper and track plates, spikes, pins, clips, screws and anchors.
They have also to be fastened to each other to provide continuity of track.
C4-6.1 Dogspikes
Dogspikes are used to hold the foot of the rail in place in timber sleepers. They are hammered through a hole in the sleeper plate into a pre-drilled smaller hole in the sleeper. They hold the rail to “gauge” and prevent the rail from lifting. There are two dogspikes on each rail on each sleeper.
Figure 62 - Dogspike
C4-6.2 Lockspikes
They are used to hold sleeper plates and track plates to sleepers and turnout timbers.
They come in 2 sizes, the shorter spike (L6) for sleepers (black) and the longer (L1) for turnout timbers (red).
Figure 63 – L1 lockspike
C4-6.3 Dogscrew
The dogscrew (see Figure 64) is an alternative fastener to the dogspike.
The dogscrew consists of a 19mm threaded shank with a 22mm shoulder below the flange. On top of the flange is a 6-lob designed to fit an E24 drive socket.
The dogscrew provides greater vertical holding force than the dogspike.
Figure 64 – Dogscrew
C4-6.4 Lockscrew
The lockscrew can be used instead of lockspikes. The lockscrew consists of a 16mm threaded shank with a flange and 6-lob head, the same as the dogscrew.
There are two types of lockscrew:
Small flange – for general use (see Figure 65).
Figure 65 – Small flange lockscrew
Lockspike
Large flange – for use with the automatic magnet pickup machine used by production gangs (see Figure 66). This type cannot be used on rolled Pandrol plates because of the flange interferes with the rolled shoulder and does not sit flush on the plate.
Figure 66 – Large flange lockscrew
The lockscrew provides similar cross-sectional strength to the lockspike.
Figure 67 – Dogscrew and lockscrew in track Advantages and disadvantages
The benefits of using the dogscrew/lockscrew include:
• The dogscrew/lockscrew uses a screwing action for insertion reducing potential injuries from flying objects and swinging of hammers.
• The dogscrew has greater vertical holding power and should remain tight for a longer time in comparison to a dogspike.
• The dogscrew/lockscrew only requires to be placed upright in the hole before screwing-in where as the standing of a dogspike requires tapping in.
• The dogscrew/lockscrew is galvanised for longer life.
The disadvantages are:
• Sleeper boring hole sizes are different to dog/lockspikes and care will be required when ordering pre-bored sleepers. The dogscrew has a 17mm diameter bored hole (21mm for dogspike) and 14mm diameter hole for the lockscrew (16mm lockspike).
• Additional equipment is required to insert and remove these screws.
C4-6.5 Screw spikes
They are screwed into place and are used to replace lock spikes on timber sleepers and also in preset holes on concrete bearers a turnout. Special helical washers are used to ensure the screw does not vibrate loose (see Figure 68).
Do not insert screw fastenings into existing dogspike or lockspike holes as the sleeper will split.
Figure 68 – Screw spikes and helical spring washer
C4-6.6 Elastic or spring fastenings
“e” clip
These are elastic steel clips (see Figure 69 to Figure 71).
Figure 69 – different types of ‘e’ clips They are used to hold the flange of the rail in place.
They are attached to the sleeper plate and hold the rail flange with a very strong grip.
Because they hold so strongly they are also used as anchors.
Certain shapes and sizes are used for different purposes. eg timber and concrete sleepers and turnout bearers and around insulated joints to ensure the track circuits are not affected. Plastic insulating pads and spacers are used on concrete sleepers to ensure the track circuits are not affected and to keep the rail in the correct position.
Figure 70 - Low profile clips in use
Standard profile Pandrol E Clip ‘e’ 2003
Low profile Pandrol E Clip‘e’1629 (Blue)
FOR USE WITH CONCRETE SLEEPERS AT INSULATED JOINTS
Flattened Toe area
Smaller, 16mm dia rod
Low profile Pandrol E Clip‘e’1627 (Red) FOR USE WITH TIMBER SLEEPERS
AT INSULATED JOINTS
Figure 71 – Standard ‘e’ clip on concrete sleeper Fastclip
These are a type of fastening for concrete sleepers that are used to hold the foot of the rail in place and reduce rail creep (See Figure 72 and Figure 73). They are applied laterally and have lugs built into the sleepers to hold the clip.
Insulating pads and insulation on the toe of the clip preserve the track circuits.
Figure 72 – Fastclip sleeper assembly
Figure 73 - Fastclip FC 1507 with insulator attached Insulating pads
In concrete sleepers a rail seat bearing pad made from high density polyethylene (HDPE) is placed between the rail and the sleeper to cushion the impact of loads. (See Figure 72 and Figure 74) The pad also acts as an insulator between the rail and the sleeper for signal current i.e. to stop the current passing across from rail to rail.
Figure 74 – ‘e’ clip rail seat pad and biscuit
Small insulating pads (biscuits) are placed between ‘e’ clip fastenings and the foot of the rail. (See Figure 75). They act as an insulator between the rail and fastenings and also keep the correct gauge. Fastclip systems have an insulator on the toe of the clip. (See Figure 76).
Figure 75 – ‘e’ clip biscuit Figure 76 – Fastclip toe insulator
C4-6.7 Zero toe load fastenings
Zero toe load fastenings are steel caps placed on Pandrol housings. When the Pandrol e-clip is inserted it rests on the top of the cap (See Figure 77 and Figure 78.) No toe load is imposed on the rail. The fastening system maintains gauge and limits vertical movement of the rail It is used on transom topped steel bridges to allow free longitudinal movement of the rail through the fastenings.
Figure 77 – Zero toe load fastenings
Figure 78 – Zero toe load fastenings on a guard rail
C4-7 Anchors
Rail Anchors are spring steel clips attached to the rail flange (see Figure 79). They lock the rail to the sleepers and stop the rails from moving longitudinally. (along their length).
This movement is called rail creep. The rail anchor presently in use is the “Fair” type.
Figure 79 – Fair type rail anchor
C4-8 Rail
C4-8.1 Parts of the rail
The various parts of the rail, are known as the “head”, the “web” and the foot (also called the flange). The internal angles formed where head, web and foot meet are known as
“fishing angles” or “fishing surfaces”. The names of the different parts of a rail are shown in Figure 80.
The surface of the rail head which contacts the wheel treads is referred to as the “running surface” and the side of the head which contacts the wheel flanges is known as the
“gauge face”.
Figure 80 – Parts of the rail
C4-8.2 Rail types
It Is important that track maintenance staff be able to recognise the various sections of rail used in the RailCorp system.
There is a manufacturer's brand on the web of each rail. The rail brand shows:
1. The name of the manufacturer.
2. The year the section became Australian Standard.
3. The section of rail.
4. The month and year the rail was rolled.
The "heat" number, which gives the batch or ingot from which the rail was rolled is found on the web of the rail on the opposite side of the rail brand.
If there is no rail brand, you can identify the rail by its size.
Running Surface Gauge Corner Region Field
Corner Region
Gauge Face
Fishing Surfaces
Top of Foot
Bottom of Foot
Foot (also known as the flange)
Gauge Point (16mm from top) Head
Web
Figure 81 – Modern Rail identification
Figure 82 – Old Rail identification
C4-8.3 Rail size
If there is no rail brand, you can identify the rail by measuring its height and head and foot widths (See Table 1).
Rail height Foot width Head width
60 kg/m 170 146 70
53 kg/m 157 146 70
50 kg/m 154 127 70
47 kg/m 141 127 70
80 lb/yd 136.3 127 63.5
Table 1 – Common rail dimensions 60H BHP XI\2000
1765736 A Rail brand
Heat Number
Rail weight
Head Hardened Manufacturer
Rolling date 60 H BHP XI\2000
C4-9 Rail Joints
C4-9.1 Mechanical joints
At a mechanical joint 2 fishplates (bars of steel) are used with fish bolts, spring washers and nuts to mechanically join the rails together. The joint is between two sleepers.
The standard variety is the "bar" type with 6 fishbolt holes.
Figure 83 – mechanical joint with fishplates and bolts
C4-9.2 Insulated Joints
Insulated Joints are used in track circuited areas where the rails form part of the Signalling System. The joints are placed in the track to prevent the flow of electricity between sections of rail. They divide and isolate the electrical circuit that is used to control the operation of signals, Level Crossing lights and bells, warning lights etc.
There are three types:
Mechanical insulated Joints - Manually constructed on site. An insulating (non-conducting) material or “fibre” between the rail ends and between the rails, fishplates and fishbolts prevents them from touching or making contact. Mechanical insulated Joints consist of:
• A fibre end post in the rail gap to isolate the two rail ends.
• Shaped liners to isolate the fishplates from the fishing surfaces of the rail.
• Ferrules, or fibre tubes, around the fishbolts to isolate them from the fishplates and the rails.
These are not available for 60kg track and must not be used in CWR or concrete track.
Bonded or Glued Insulated Joints – Specially manufactured and welded into place.
Joints are now manufactured with the insulating end post placed at an angle of 15°. This reduced the potential impact on the joint.
Glued insulated joints have several advantages over mechanical insulated joints.
• The joint is stronger.
• Being a rigid joint there is less chance of damage to the insulation through opening and closing of the joint.
• The joint can withstand more compression and tension.
Figure 85 – Bonded Insulated Joint
Figure 86 – 15° end post
Insulated Plate joints (Benkler joints) – in these joints the fishplate is completely enclosed in insulation and the joint is fastened together with huck bolts. They are only used in turnouts.
Figure 87 – Benkler Joint
C4-9.3 Junction plates
These are normally found in yards and sidings. They are used to join different sections of rail mechanically. They bring both the running surfaces and gauge faces into line.
To identify junction plates:
Stand with your back to the larger size rail RI = Right hand inner plate.
RO =Right hand outer plate.
LI =Left hand inner plate.
LO =Left hand outer plate.
Junction Plates have presented numerous maintenance problems. Often it is difficult to prevent joints becoming ‘foul’ and for this reason “Junction Rails” are now widely used.
Figure 88 – Junction plate
C4-10 Rail welds
Rails are supplied from the manufacturer in 27m lengths. They are welded into longer 110m lengths at RailCorp’s Rail Fabrication Centre at Bathurst using the Flashbutt welding process. When rail is laid in track it is then welded into continuous lengths (Continuous Welded Rail or CWR) using the aluminothermic welding process. This process is also used to replace defective lengths of rail in track and to install bonded insulated joints and junction rails.
C4-10.1 Flashbutt welding
In Flash butt welding two rail ends are brought together and supplied with an electrical current. This melts the rail ends, which are then squeezed together under hydraulic pressure, joining the two rails.
The resulting excess material around the edge of the weld is sheared off and ground to produce the finished weld.
The high heat concentration affects the grain structure of the steel, and results in uneven wear in the vicinity of the weld under traffic. To overcome this, the weld area is heat
Larger Rail size (107)
Smaller Rail size (90)
Label – this is “LI” or Left inner
treated. This process allows the altered grain structure within the weld to revert to the original grain structure of the rail steel.
Figure 89 – Rail ends ready for
welding
Figure 90 – Flashbutt weld
Figure 91 – Grinding the weld Figure 92 – Finished weld
C4-10.2 Aluminothermic welding
In Aluminothermic Welding, parts are joined by utilising liquid metal as filler metal to form a fusion weld with the two rail ends.
The rail ends are aligned 25mm apart and enclosed in a two or three part mould. Rail ends are preheated with a flame jet using oxygen and propane gas. After heating the rail ends a crucible containing the aluminothermic powder (the portion which is made up of iron scale to aluminium) is placed above the gap and ignited. The reaction produces heat and melts the metal in the portion. When the reaction is completed the crucible is tapped and the molten metal flows into the mould.
The excess material around the edge of the weld is sheared off and ground to produce the finished weld.
Figure 93 – Preparation for aluminothermic welding
Figure 94 – Weld in progress
Figure 95 – Completed aluminothermic weld
C4-10.3 Junction rails and welds
In mainlines, Junction Rails (or Junction Welds) are used to join different size rails together.
A junction rail is a forged rail of two different sizes used to connect different sections of rail.
A junction weld is a specialised aluminothermic weld used to weld together different sections of rail.
C4-11 Rail lubricators
Rail Lubricators are used to help reduce friction between the gauge face of the rails and rolling stock wheels and flanges.
If friction is reduced, wear of both these items is reduced which results in cost savings for the owners and the operators of the rail system.
Gauge face lubrication is not normally effective in reducing wheel squeal.
C4-11.1 Types of lubricators
Single pump, single blade lubricators are the preferred type.
There are two types of lubricators in use, the P&M (Fessl) and the RTE 25.
There are two types of lubricators in use, the P&M (Fessl) and the RTE 25.