LCC Based Permanent Way Strategies Peter Veit peter.veit@TUGraz.at
Content - methodology of evaluation - analysis of present situation - quality behaviour of track
Q = Q 0. e -b.t Life Cycle Costs based Strategies experience: a good track behaves well, a poor one deteriorates faster This quality behaviour is proofed with the track recording car data from 1992 to 1999 AND all data show, that it is not possible to surpass the initial quality! deterioration depends on the present quality level costs of operational hindrances = LCC investment + maintenance
investment characteristics of standard kilometre service life planed maintenance small maintenance Input Data – Working Cycles based on good subsoil conditions Calculating of all track work given in the cycle including their costs of operational hindrances life cycle cost
Methodology of Evaluation Comparing both cycles shows the benefits of rails with the profile 60E1 for this standard kilometre Comparing track strategies results in stable rankings, though absolute life cycle cost are not stable.
Input Data Input data were not available from data banks describing the present (quality) situation of permanent way because we need to predict what happens if… (behaviour of track!) research in track behaviour the data do not exist, but the knowledge (still) exists! step 2 TIME?! started in 1998 WORKING GROUP implemented at ÖBB between 1996 and 2002 step 1 ! basic strategies !
Cost Driver Speed < 160 km/h 1. Initial track quality defines maintenance requirements 2. Subsoil quality: 1 to 8 times 3. Switch density: 1 unit equals 450 m track 4. Alignment (Radii, ….): 1 to 3 5. Cost of operational hindrances: up to 30% 6. Traffic density: ~ linear, if superstructure and substructure matches the traffic requirements 7. Quality of motive power units: ± 10%
cost factor maximal average minimal radii [m] Track Costs for Different Radii Cost differences up to 1:3 even on good subsoil!
annual cost [%] Cost Analysis 100% 67% 50% 47% 57% 33% 67% 17% Permanent way strategies aim to extend service life of track Reducing maintenance accepting a reduction of service life is highly uneconomical Operational costs caused by maintenance work (or a lack of maintenance) are decisive
15.0% 10.0% 5.0% Differences in total annual cost compared to present situation 0.0% -5.0% -10.0% age: 35 years -15.0% Motive power unit E 1044-200 = + 0,0% D E A B G C R > 600 m R < 250 m F 400 < R < 600 m 250 < R < 400 m Radii Economic Impacts of Different Motive Power Units new locos! Conventional track user charges do not include any incentive to invest in rolling stock quality!
Q = Q 0. e -b.t Quality Behavior of Track Austrian quality figure “MDZ” is based on calculated differences of accelerations resulting from track irregularities
Behaviour of Track Quality Florian Auer, TUGraz, now ÖBB
excellent quality, slow deterioration less quality, faster deterioration Behaviour of Track Quality Present status of track and its history allows to calculate deterioration factor b for specific sections and so to define section specific investment and maintenance strategies
time quality effect of maintenance action deterioration total quality function threshold value E technical service life quality Behaviour of Track Quality
time but quality Behaviour of Track Quality
0 100 200 300 400 500 600 700 800 900 0 days -5 -10 Q = Qme-bt -15 threshold value Q = Q0e-ct -20 -25 -30 MDZ-A Behaviour of Track Quality fighting the causes sustainable maintenance Q0 Q = Q0e-bt Qm Qtv fighting the symptoms short term results Description of quality needs status data AND its behaviour over time!
time quality effect of maintenance action deterioration total quality function conform threshold function E quality Conform Threshold Function
Q = Q0e- b t b number of interventions 10 15 Behaviour of Track Quality Analysis show a not linear behaviour of bi, becoming critically after a certain number of tamping cycles (good subsoil conditions) NEEDS VERIFICATION
b = f(basic conditions) Behaviour of Track Quality Q = Q0e-bt MAIN BASIC CONDITIONS track superstructure - initial quality - type of superstructure - radii (speed) - traffic density - subsoil quality - ? - ? turnout - additional: operational conditions
Summary Degradation of track depends on track quality itself (ΔQ ~ Q) That is the reason for the main importance of initial quality For describing track quality we need to know the actual quality figure PLUS its behaviour over time Development of track quality over time should be presented as part of recording car data analysis