Presentation on theme: "Review of Wheelset Flange Height and Thickness Limits in GMRT2466 (RIS-2766-RST) Dr Gareth Tucker 4/12/17."— Presentation transcript:
1 Review of Wheelset Flange Height and Thickness Limits in GMRT2466 (RIS-2766-RST) Dr Gareth Tucker4/12/17
2 ScopeCan flange height and thickness limits be changed to allow more wear?What are the historic reasons for wear limits in GMRT2466?What hazards are controlled by flange wear limits?How does flange wear affect negotiation of obtuse crossings?How do GMRT2466 limits compare with the LOC & PAS and WAG TSIs?What additional controls might be required if flange wear limits were relaxed?Is there a benefit in higher flange wear allowance?
3 Flange height and thickness limits in GMRT2466 issue 3 Can 24mm flange width and 36.5mm flange height be applied to all profiles?Could wear allowance be extended further?Do TSIs allow more wear than RGS/RIS?
4 Previous wheelset standards Standard NoIssueDateTitleBR MT 2881Jan 1991Wheelset tread standards and gaugingGM/TT0115?Wheelsets: In-Service Safety and Maintenance AttentionGM/TT0089Feb 1994Geometric Interfaces Between Railway Wheelsets and TrackGM/RT2026May 1994Wheelsets: In Service Safety and Maintenance Attention2July 1996GM/RT2466June 2003Railway WheelsetsGM/GN2497Dec 2007Guidance on Railway Wheelset Tread, Gauging and Damage IdentificationAug 20083Feb 2010RIS-2766_RST2017Rail Industry Standard for Wheelsets
5 Origin of requirements? New Tyre Profiles For British Railways, Railway Gazette, January 1968Discusses development of RD4 wheel profile (=P8)Suggests flange height limit of 1.44 inches = 36.6 mmSuggested minimum flange thickness of 0.79 inches = 20 mmThese limits appear to be based on RIV (International Wagon Regulations) requirementsVDYN 209 Flangewear Limits, 1990Suggest flange wear allowance of 5mm to limit amount of material removed at turning in order to restore full flange widthCurrent limits are 4 – 5 mmBDYN 143 P10 Profile limits and UIC leaflet 510-2Suggests P10 (an S1002 variant) for GB use should have same wear limits as P5
6 TSI and RGS wheelset limits 𝐵 10𝑚𝑖𝑛 = 𝑆 𝑚𝑖𝑛 − 𝐴 𝑚𝑎𝑥 2 =23.5 => 𝐵 13𝑚𝑖𝑛 =23TSI (wheels > 840 mm ⌀)RGSAmax13631363.3Amin13571358Smin1410xBmin2224 (exc P9)
7 Back to back measuring point GB ApproachBack-to-Back measurement with the axle unloaded, or level with the centre if loadedVEHICLE LOADEN ApproachBack-to-Back and Front-to-Front measurement at rail level under vehicle loadAxle deflection:Outboard bearings: ReducesInboard bearings: Increases
8 Hazards controlled by limiting wheel wear? Flange back strikes open switch.Flange back makes contact with check rail before checkrail entry point.Flange back makes contact with wing rail before wing rail entry point.Flange hits the end of a closed switch.Flange makes contact with a closed worn switch blade with a low contact angle (relative to horizontal).Wheel with high tread wear makes contact with a fish plate on rail at maximum headwear allowance.High angle of attack in curves due to thin flanges.Allowing wheels to run longer between turning cycles could lead to low (or high) conicity.Flange strikes obtuse crossing nose.
9 Freewheel passage through open switches, checkrail entry points and wing rail entry points (hazards 1 – 3)T783 Wheelset and switches and crossing compatibility investigation, 2009
10 Check rail and wing rail entry points Hazard 1 & 2 TSI maximum freewheel passage at check rail entry1380 mmTSI min flange front to flange back1382 mmNR/SP/TRK/001 maximum freewheel passage at check rail entry1376 mm (113A vertical)1357 mm (NR60)GMRT2466 flange front to flange back1382 mm(P1, P6, P8, RD9, P11, P12)1385 mm (P5, P10)
11 Freewheel passage through open switches Hazard 3 GMRT2466 min flange front to flange back:1382 mm (P1, P6, P8, RD9, P11, P12)1385 mm (P5, P10)TSI min flange front to flange back: 1382 mmTSI max freewheel passageThrough open point: 1380mmGCRT5021 max freewheel passage through open points: 1375mmFor ‘historic’ designs (113A vertical) previously applied limits can be used (GIRT7004) : 1388mmNR/L2/TRK/6100 max freewheel passage for 113A vertical points: 1382 mm
12 Limits on flange wear to control Hazard 1 – 3 ? Hazard 1 – 3 not directly affected by flange heightNetwork Rail standards control the maximum freewheel passage in 113A vertical points to 1382 mmGCRT5021 (referring back to GIRT7004) effectively permits a maximum freewheel passage of 1388 mmBased on the Network Rail limits, all profiles could be given a minimum flange thickness of 24 mmThis would allow the flange back to just touch an open switch (as is currently the case for P1, P6, P8, P11, RD9 & P12)GCRT5021 should be updated to reflect the freewheel passage limits that are currently being used by Network Rail
15 Clearance assessment Max side wear 0.89 mm overlap 1.86 mm overlap 27 mm flange width, 33 mm flange height24 mm flange width, 36.5 mm flange height23 mm flange width, 36.5 mm flange heightNew P5Max side wear0.89 mm overlap1.86 mm overlap1.86 mm overlap1.86 mm overlapMax head wear0.93 mm overlap0.93 mm overlap0.93 mm overlap
16 Limits on flange wear to control Hazard 4? Already possible for new wheels and worn wheels to scuff a switch toe (if the wheelset completely closed up stock rail)Further reducing the flange width doesn’t increase the level of interference with a switch toeLevel of inference is dependent on flange angleIn the clearance assessment assumed worn flange angle is 76⁰Is flange width an indirect control of flange angle?
17 Worn P5 flange angle vs flange width 468 worn P5 wheel profiles measured as part of T889
18 Contact angle with a worn switch blade (Hazard 5) NR/L2/TRK/0053 Hazard 2Maximum 3mm side wear on stock rail within first 500mm of switchTGP8 does not make contact below 60⁰ line in first 500mm of switchNB1 TGP8 is based on cross section of a new P8NB2 Contact angle assessment is very sensitive to the assumed worn switch shape
19 Contact angle? 27 mm flange width, 33 mm flange height New P5
20 Limits on flange wear to control Hazard 5? Reducing the minimum flange thickness for a P5 appears to increase the risk of low contact angle with worn switchesAlso relevant to other wheel profiles with low flange heights (P10/S1002)Assessment has been based on maximum flange wear with zero tread wearHigher flanges (i.e. tread wear) reduce the riskMight be beneficial to modify method to inspect worn switch railsP1, 24mm worn flange widthP8, 24mm worn flange widthP5, 24mm worn flange widthP10, 24mm worn flange width
21 Clearance to fishplates (hazard 6) Possible to increase flange height limits to 39 mm (with 0.5 mm clearance)Or 38 mm (with 1 mm clearance)
23 Limits on flange wear to control Hazard 7? A wider flange way clearance (narrower flange) can slightely reduce angle of attack because the increased flangeway clearance allows wheelsets to steerThis only works down to a certain, minimum curve radius
24 Link between flange width and conicity (Hazard 8) 468 worn P5 wheel profiles measured as part of T889
25 Limits on flange wear to control Hazard 8? In the sample of wheels considered, wheels with thinner flanges are more likely to have a lower conicityFlange width is not a direct control over conicity35% of wheels with a flange width over 27 mm also have a conicity lower than (when combined with new CEN60E2 rail)Lower flange widths could be permitted without creating wheels with conicities lower than the existing spread
26 Interaction with obtuse crossings (Hazard 9) Reduced flange width increases clearances to the crossing noseIncrease flange heights reduce the effective unguided length* T560 created a spreadsheet tool for investigating clearances in obtuse crossings
27 Summary x NoHazard/considerationGive all profiles 24 mm min flange width?Give all profiles mm max flange height?Use TSI limits?Further reduce flange width limit?Further increase max flange height?1.Flange back hits open switch2.Flange back contact with check rail before entry point3.Flange back contacts wing rail before entry point4.Flange tip hits the end of a closed switch5.Interaction with closed switch?6.Clearance to fishplate7.Angle of attack in curves8.Conicity9.Obtuse crossingsx
28 Conclusions and recommendations The flange height limit for P5, P10 & P11 could be increased to 36.5 mmPending review of worn switch monitoring it may be possible to introduce 24 mm flange width for P5 and P10A clearly defined maximum freewheel passage for 113A vertical points should be included in GCRT5021Use of TSI flange width limit should only be used in combination with full TSI wheelset dimension controlsIt appears existing flange width limits are based on maximising wheel life, with a flange wear allowance of around 5mm as suggested in VDYN 209If flange width limits are reduced, wheels that reach those limits will require more material to be removed at turningThere may be some benefit at the last turning cycle or giving flexibility where there is limited lathe capacity