(IX-B4, 2012 
International Archives of the Photogrammetry, Remote Sensi 
XXII ISPRS Congress, 25 August — 01 
® AGH University of Science and Technology, 
Sensing, , 
ABSTRACT: 
scanners, which capture data in a continuous way, 
model. 
1. INTRODUCTION 
11 Goal 
Measuring of railway structure clearances is a practical issue, 
performed all over the world, using various measuring systems. 
The measurement is aimed chiefly at demonstrating the limits 
of space that no structure (e.g. a building) may cross. Clearance 
Measurements can be performed either statically, or 
dynamically in the course of the measuring system's travel on a 
railway track. 
The authors of this 
and 
The 
paper are presently implementing a project, 
one of its tasks is developing a prototype of such System. 
project is being carried out by rescarch team from the AGH 
University of Science and Technology, upon the commission of 
Polish Railways. The main goal of the project includes research 
on à prototype of a system of rail clearance measurement and 
rilway codification. In this paper, the authors focus on the first 
Part of the project, i.e. developing of a prototype of a measuring 
System. To attain that goal, the authors have reviewed the 
CXisting Systems (Section 1.2), and next, selected two solutions, 
which were examined, and for which test measurements 
described in Section 3 were performed. 
ased on experiments, which had been conducted, the authors 
Proposed a Prototype of measuring flatcar to be tested in 
subsequent stages of the project (Section 4). 
* 
Corresponding author. 
  
KEY WORDS: rail clearance, measurement system, photogrammetry, 
ng and Spatial Information Sciences, Volume XXXIX-B4, 2012 
September 2012, Melbourne, Australia 
RESEARCH ON THE PROTOTYPE OF RAIL CLEARAN CE MEASUREMENT SYSTEM 
P. Kohut*, S. Mikrut?, K. Pyka 5, R. Tokarczyk? *, T. Uhl? 
“ AGH University of Science and Technology, Dept. of Mechatronics and Robotics, 30-059 Cracow, Poland 
— (pko, tuhl)@agh.edu.pl 
Dept. of Geoinformation, Photogrammetry and Environmental Remote 
30-059 Cracow, Poland - (smikrut, krisfoto, tokarcz)@agh.edu.pl 
Commission IV WG IV/2, IV/4 
laser scanning, integration, 
Measuring of railway structure clearances is a very practical issue, and the operation itself is performed all over the world using 
the limits of space that no structure (e.g. a building) 
located close to the railway track may cross. The paper demonstrates flaws and advantages of particular systems and provides a 
technological summary of measuring equipment utilized in them. In those systems the measurement of structures is referred to the 
global system of coordinates, and later, following the detection of rail heads, 
place. The preliminary analysis leads to a conclusion that the accuracy of rail clearance measurement is higher in the case of 
specialized systems as compared to universal ones. On the basis of experience 
been made to proceed with the construction of a rail clearance measurement 
Technology in Cracow. This paper presents a research on the prototype of the rail clearance measurement System constructed at the 
University. The heart of the system involves laser scanners installed on a flatcar 
drawn from literature and earlier tests, a decision has 
system in Poland, at the University of Science and 
and digital cameras. The base of the System includes 
and photogrammetric cameras, which yield digital images. 
The cloud of points obtained from a laser scanning is colorized, which causes that such information can replace a classical texture 
1.2 Examples of Railway Clearance Measuring Systems 
The project authors have reviewed the existing measuring 
systems used to determine structure clearances, systematizing 
them from the simplest ones (e.g. LaserTEC electronic rail 
gauge) to the most modern and most technologically advanced 
mobile systems. 
Based on their functionality, those systems were divided into: 
- those dedicated to railway-specific applications, e.g. British 
Balfour Beatty Rail Technologies (BBRT,2011), German 
LIMEZ I, II, and III (Schewe et al., 1999; Meier, 2009) and 
Zoller + Fröhlich Profiler (Zoller+Fröhlich, 2010), 
- two-way systems (e.g. Italian L-KOPIA / LKO B1 Clearance 
Laser System (L-KOPIA, 2012), 
- universal mobile systems, with an option of rail clearance 
measuring, e.g. Austrian RIEGL system (Riegl, 2011) and 
German 3D Mapping Solution. 
Systems currently in use are based mainly on three groups of 
methods: 
a) the photogrammetric method, 
b) the method of light profiles, which are applied by the laser 
light and recorded by means of a high-speed digital camera, 
c) the method based on laser or radar scanner measurements. 
Those most advanced systems combine the above-referenced 
measurement methods. Within the research framework, the 
systems were reviewed, and features of measuring devices were 
summarized as regards their flaws and advantages, so that the 
proposed prototype could be as much optimal, as possible. On 
the basis of those research works, the authors have worked out