School of Surveying and Spatial Information Systems

The University of New South Wales

Railway Surveying: New South Wales and Europe

by S. C. North

Supervised and edited by J. M. Rüeger

October 2002

The techniques and equipment used by the surveyors of the NSW Rail Infrastructure Corporation (RIC) are reviewed and compared to those adopted in countries like Germany, France, Sweden and Switzerland. These countries are used in the review because of their use of advanced technologies and the fact that Germany and France run trains at speeds of 200 - 400 km/h. Surveyors use specialised equipment and techniques in the construction and maintenance of railway tracks.

For the setting-out of tracks, one has to look at the techniques for the establishment and the use of survey control within the railway corridor to achieve high accuracy and at the gathering and preprocessing of the track data before the actual setting-out of the track. The survey equipment used in the setting-out of railway tracks includes offset prisms and specialised reflector rods.

Figure 1: Track measurements with track bar and reflector rod in NSW, Australia (RIC 2001)

The maintenance of railway tracks involves the various methods and equipment that are used to measure the existing track position. Electronic tacheometers, track bars, magnetic track attachments and reflector rods are employed to determine the position of the track. Figure 1 (RIC 2001) shows the procedure with a Leica TPS1101 electronic tacheometer, a reflector pole and a track bar. An alternative method is to use a cart based track measurement system such as the German 'Surver' system illustrated in Figure 2 (Müller 2000). Figure 2 depicts a Geodimeter System 4000 RPU on the track measuring cart and a Geodimeter 4000 electronic tacheometer on the side of the track. These systems are equipped with reflectors so the position of the cart can be determined whilst being pushed by hand or by motors on the cart. The track measurement carts have onboard sensors to measure (in real-time) the gauge width and the along-track and across-track tilts. In lieu of robotic electronic tacheometers, differential GPS can be used to record the position of the track measurement cart. The Profilometer Geo++ SURVER represented in Figure 3 (Halle 2000) is such an example used by the French railways. Track measuring trains are also used by some railways; the “AK Unit” is used in NSW and the “LIMEZ” unit in Germany. These trains measure the track position whilst travelling at speeds greater than 20 km/h. The measurement trains are mentioned even though these systems are not used for the set-out and precision measurement of the tracks.

Figure 2: German Track measuring cart SURVER with a Geodimeter 4000 electronic tacheometer
(on the left) and a Geodimeter RPU on the rail cart
(after Müller 2000)


Figure 3: Profilometer Geo++SURVER in use with the French railways (after Halle 2000)


Some recommendations have been made to the Rail Infrastructure Corporation of NSW concerning the reflector rods and offset prisms used for railway surveying as well as new equipment to record the track position. A new type of track reference mark (see Figure 4) is recommended as are measures to protect these from damage. The use of robotic motorised electronic tacheometers is promoted as is the implementation of concrete base slab tracks.

Figure 4: Track reference marks used by the Swiss railways (Riesen et al. 1994)

Further Information
For more information, please contact:

Assoc. Prof. J. M. Rüeger

School of Surveying and Spatial Information Systems
University of New South Wales

Phone: +61-2-9385-4173
Fax:      +61-2-9313-7493

Mr. G. Gaggin


Rail Infrastructure Corporation
Engineering Design
Survey Section, Level 18
477 Pitt Street
Sydney NSW 2000

Phone:  +61-2-9782-1800
Fax:      +61-2-9782-1811

Mr S. C. North