PANDROL PANGUARD™ - Pandrol USA

PANDROL PANGUARD

PANGUARD
In vibration and noise sensitive areas, most track designs in use around the world work on one of two principles
to reduce groundborne vibration – either by increasing the mass of the resiliently supported track structure or
by reducing the stiffness of the support. The lower the track stiffness which can be achieved, the lower the
resonant frequency becomes, and the better the vibration attenuation which results. But before the
Pandrol PANGUARD system, large vertical deflections also resulted in unacceptable lateral movement of
the rail head.
The Pandrol PANGUARD system delivers an assembly with both very low vertical stiffness and minimal rail roll
and delivers exceptional vibration reduction performance at a much lower cost than floating slab.
In the Pandrol PANGUARD assembly, the rail is supported under the head and in the web with large rubber wedges, leaving the
foot of the rail suspended. The rubber wedges are held in place by cast-iron side brackets which are in turn fastened either to a
shoulder cast into a concrete tie or block, or to a baseplate fixed to the track base using either bolts or screwspikes. The
baseplate system can be used on slab track, wood ties or on steel or concrete bridges.
The assembly allows large vertical deflections, and although it is resilient in a lateral direction, rail roll is minimised because the
forces applied to the rail head are reacted much closer to their line of application than in a conventional fastening.
Key components
Cast in Shoulder Assembly
Side support bracket
Rubber wedge
Cast iron
locking
wedge
Typical key dimensions
Inclination of the rail is provided in the concrete tie or
slab into which the assembly is set.
Height of rail base above concrete level: 5/8" (17mm)
Length of rubber rail supports: 9 7/8" (250mm)
Width of assembly along rail axis: 5 7/8" (150mm)
Width of assembly perpendicular to rail axis: 13"
(330mm)
Shoulder

Key components
Baseplate Assembly
Rubber wedge
Side support bracket
Serrated Adjustment
Washer
Cast iron
locking
wedge
Typical key dimensions
Inclination of the rail is provided in the baseplate.
Height of rail base above tie: 1 3/16" (30mm)
Length of rubber rail supports: 9 7/8" (250mm)
Width of assembly along rail axis: 7 7/8" (200mm)
Width of assembly perpendicular to rail axis: 19 1/4"
(490mm)
Baseplate
Hook In
Shoulder
Advantages
•Very low dynamic stiffness – 4.28 X104 lb/in (7.5kN/mm) or less leads to:
✓ minimal rail roll
✓ a low vibration performance similar to floating slab track but
- at a much lower cost and
- with much better access for maintenance or adjustment
•Reduces vibration and secondary noise significantly
•Very low profile:
✓ can fit within existing restricted rail heights to:
- provide a retrofit solution in areas where space or cost prohibits the use of floating slab track
- reduce tunnel diameters and costs for new track construction, giving very large savings in project costs.
•All components are easily replaced for ease of maintenance
•Low longitudinal stiffness avoids load transfer between rail and bridge on thermal expansion
•Longitudinal creep resistance can be adjusted in situ to suit requirement
•Uses proven materials technology

PANGUARD
Application and Installation
The Pandrol PANGUARD system is available in two different versions – as a baseplate assembly, or as a
cast-in assembly. Both offer the same low stiffness and consequent high vibration attenuation capability.
The choice as to which to use depends mainly on the preferred method of installation. The cast-in version
on ties or individual rail seat blocks is particularly suitable for top down construction and for retrofit in
place of existing ties or blocks. The baseplate assembly has been designed in order that it can be easily
slid into place under the rail as a retrofit in place of existing less resilient rail fasteners. As with other
baseplates, it can also be used for new construction with either the top down or bottom up method.
Cast-in Assembly
Baseplate Assembly
Installation Tools
The Pandrol PANGUARD system fastens the rail at the web unlike
conventional fasteners that clamp the rail base. Therefore slightly
different techniques are used to install this assembly. However, all
conventional forms of track construction can be applied when
fitting PANGUARD and there is no need for expensive or
complicated equipment. The principle of installation is to apply a
lateral precompression to the rubber supporting blocks. This force
maintains the rail position laterally while allowing it to deflect in the
vertical plane. Installation is a one man operation using a simple
hand tool to apply the clamping force.

Pandrol PANGUARD is suitable for application on concrete ties, wood ties, slab track and bridges. The assembly features height
adjustment within the assembly itself, or by shimming under a baseplate. Lateral adjustment is also available, either within the
assembly or via the baseplate.
Bridge Application on Concrete Ties in Ballast
Tunnel Application on Concrete Slab
Baseplate Application on Concrete Slab
Laboratory Testing
Before its first installation in track, the Pandrol PANGUARD
system was tested extensively in the laboratory. A range
of tests and measurements were made, as follows:
• Repeated inclined dynamic load test, run for more
than 4.5 million cycles
• Dynamic stiffness of the assembly
• Longitudinal stiffness and creep properties
• Electrical resistance
• Accelerated ageing (corrosion)
• Resistance to chemicals used on the track
• Fire resistance
Laboratory Test Reports are available on request.
Inclined Dynamic Stiffness Test Arrangement

PANGUARD
Suitable Applications
Applications of Pandrol PANGUARD make use of the product’s unique characteristics. Its low overall
height makes it very suitable where lower stiffness is required in existing track, but the rail head level
cannot be raised. The very high level of vibration attenuation achieved with the system can be used to
control ground vibration – for instance from trains running in tunnels, or to reduce the noise emitted from
vibration of structures such as bridges or viaducts. Examples of two applications are given below – one
in which a primary objective was control of ground vibration and the other in which it was used to
investigate the system’s capacity to reduce noise from a bridge.
Case Study 1
London Underground, UK
Installation of Pandrol PANGUARD on concrete ties in place of wooden ties with baseplates.
The installation was intended to reduce groundborne vibration from tunnels.
Rail Spacing Axle Load
BS113A 0,9m 11 tons
Invert Vertical Vibration
90
87.3
Vibration velocity dB (ref. 5E-8m/s)
80
70
60
50
40
Before
After
69.7
Insertion Loss – 17.6 dB
Note - Bars show total
vibration levels
30
50 100 200 500 1000 2000
Frequency (Hz)

Case Study 2
Railtrack, UK
Installation of Pandrol PANGUARD on concrete ties on a ballasted steel bridge structure.
The installation was aimed at the reduction of secondary noise resulting from vibration of a steel bridge under rail traffic.
Rail Spacing Axle Load
BS113A 0,65m 28 tons
90
Noise under bridge (4m below bridge)
Sound Pressure Lmax dB(A) (ref 20E-6Pa)
80
70
60
Insertion Loss – 6.7 dB(A) 50
Note – Bars show total
sound pressure levels
50
63
80
Before
After
100
125
160
200
250
315
400
Frequency (Hz)
500
630
800
1000
1250
1600
2000
2500
3150
4000
5000
83.4
76.7
Total
dB(A)

Pandrol USA, LP
501 Sharptown Road, P.O. Box 367
Bridgeport, NJ 08014
Phone (856) 467-3227 or (800) 221-CLIP
Fax (856) 467-2994
Website www.pandrolusa.com
Pandrol Canada Limited
6910 34th Street
Edmonton, Alberta T6B 2X2, Canada
Phone 780-413-4281
Fax 780-413-4283
‘PANGUARD’ is a registered trademark of Pandrol USA, LP
The technical information given in this brochure was correct at the time of printing, but the company undertakes a continuing program of
research and development and improvements may have since been introduced.
2005