Inhabilidades para los ediles

(i) Deficient packing at joggled fish plated location

It is observed that after running of CC+8+2T load, the increased generation of USFD defects due to OBS/Cupped Welds has resulted in increased population of joggled fish plated welds. The present fittings in use at these joggled fish plated joints ( i.e. ERC mark.III in reverse condition/J clip) makes the sleeper vulnerable to more impact because of lesser toe load and propensity of development of gap between rail bottom and sleeper. In fact, this has further deteriorated the situation due to crushing of rubber pads on welded joint locations. (ii) Extra stress on sleeper fastenings near weld locations Due to inappropriate dimensional tolerances formed during initial welding stage and during process of maintenance (formation of cupped welds), the rubber pad gets crushed near the weld locations require frequent renewals. In fact in this railway a practice is made to keep 2 rubber pads at each such welded joints, the frequency of renewals at these locations approximately once in 2 years against the normal renewals. (iii) Effect due to iron ore droppings

(a) Due to falling of iron ore particles on the flanges of rails, liners and ERCs, the rails and fittings are getting more corrosion compared to earlier resulting in greasing to ERCs and painting of rails to be done at increased frequency as that of corrosion prone area.

(b) Due to continuous iron ore droppings in some of the stretches the ballast is becoming caked up and therefore affecting the drainage as well as quality of tamping. This in long run will result in more frequent shallow screening/ deep screening. Consequently, as a result of reduced resilience the additional stresses are likely on sleeper/fittings. The life of fittings is getting reduced in such location. (iv) Reduced life of rubber pads in general

The experience of last 4 years has shown that other than the locations discussed vide i, ii & iii above, the available design of elastic fastenings are surviving without abnormal deterioration except rubber

pads. In fact, at several TFR locations ( other than corrosion prone area), it is noticed that lot of metal liners and ERCs are found to have further residual life whereas the condition of rubber pad are deteriorated. With the increase in loading patterns, this phenomena of crushing of rubber pads will be more and require their frequent renewal. To meet the variations in life cycle of the different fittings, it is required to adopt thick/improved rubber pads. Further, it is recommended that Through Pad Renewals on such heavier axle routes in between TFR cycle for maintaining the track parameters may be required.

5.3 Rails:

Due to dropping of iron-ore particles on flanges of rails, the corrosion in 90UTS rails are increasing compared to earlier, necessitating painting of rails at increased frequency as that of corrosion prone area, though the stretch is in non-corrosive area.

Formation of small spots on top of rail head: Due to iron ore lumps dropping on top of the rail and getting crushed under moving wheel, formation of small spots upto 2mm size noticed which are affecting the running qualities of track at a later stage.

(i) Rail/Weld Failures: The comparative statement of Rail/Weld

failure for section running CC+8+2 loads for last four years are as under:

Rail/weld Failure in CC + 8 + 2 route BAY - GTL (DN), GTL-RU (UP/SL) & GTL - NDL (SL) & NDL - GNT (Sl)

S Section 2006-07 2007-08 2008-09 2009-10

No. (upto Sep.09)

RAIL WELD RAIL WELD RAIL WELD RAIL WELD

1. BAY-GTL 2 31 1 11 - 5 - 1 (DN) 2. GTL-RU 2 109 1 66 - 43 - 10 (UP/SL) 3. GTL-NDL 1 19 1 36 3 67 1 43 (SL) 4. NDL-GNT 1 130 0 232 0 279 1 24 (SL) TOTAL 6 289 3 345 3 400 2 78

••••• In BAY - GTL Section :There was weld failure in 2005-06 mainly

on account of old 52 kg72 UTS rails which were already carried enough GMT. The same had come down considerably in 07-08 and further in 2008-09 on completion of 40 KM deep screening by BCM and renewal of old track with CTR(P) 60 Kg.

••••• In GTL-RU section, there is a phased reduction in rail/weld

failures in GTL- RU section mainly due to CTR/TRR of about 100 Kms with 60 kg rail and deep screening of about 60kms PSC track which was overdue. The track works like deep screening and TFR have lot of impact on reducing of weld failures which can be noticed in km.233 between MMPL and VNM where 7 failures have taken place in 06-07 and only one failure in 07-08 after deep screening and TFR.

••••• In GTL-NDL & NDL-GNT section, the failures have increased

in this section from 151 in 06-07, 269 in 07-08 to 349 in 08-09. Even in this current year also there are 69 failures till SEP’09. This section is having 52 kg rails of 1996-97 laid during gauge conversion. The population of skv welds are more since free rails were welded and made LWR.

••••• This section opened with 4 GMT traffic in 1997 and now GMT is

32, therefore the more weld failures may be due to increase GMT also. However efforts are being made to reduce it by carrying out TFR and Destrssing during last 2 months, and there is considerable reduction in Weld failures in last one month in GTL- NDL section.

(ii) Curves: Wear on outer rails in curves have increased,

necessitating greasing of curves once in a week/twice a week depending upon the sharpness. The wear on sharper curves in GTL- NDL section has considerably increased in the last 2 years of running of CC+8+2 in block section PNM- BMH of GTL-NDL Sction, which is having 1in 83 rising gradient with 12 curves having maximum degree up to 6, both lateral and vertical wear crossed the permissible limits. Here 14.5 KM of CTR got sanctioned on that account in 2007-08 and 2008-09. further 11 KM CTR(P) is proposed in PWP-2010-11 for MYL- DHNE section on wear account.

Similarly in GNT division on a 5.7 degree curve laid with 52kg 90 UTS rail on PSC 5 sleepers at Km.217/4-218/0 and at Km.171/8 – 172/2

with fairly uniform versine throughout its length, lateral wear on outer rail has reached 10mm and rails renewed on 3/2009 despite of provision of check rail and hand greasing of gauge face of the rail twice a week. The wear was 3mm during 6/2005 and the cumulative GMT carried by the rail is just 35% of estimated 525 GMT. The spurt of wear attributable to positive angle of attack of wheel flange aggravated by higher axle load in turn higher flange force.

However efforts are being made to do regular curve greasing to reduce wear. Use of automatic greasing machine may help in reducing the manpower and provides uniform application of grease. Manual system of greasing besides being irregular and non uniform, involves safety risk to trackmen deployed for greasing on sharp curves due to visibility problems. There is need to evolve an efficient automatic greasing system. Available systems were tried but not found to be successful on long term basis. Providing wear resistant rails on curves or reducing the frequency of replacement of outer rails of curve to 150 GMT for 52 kg 90 UTS rails may also provide relief.

(iii) Stalling : On steep rising gradients, more number of stalling

cases is noticed, especially in rainy season where the axle load is getting increased due to water content. The comparative details of stalling are given below:

Section 06-07 07-08 08-09 09-10 (Up to

SEP’09)

BAY-GTL 0 1 0 0

GTL-RU 9 3 0 0

GTL-DHNE-NDL 3 4 0 0

Due to strict vigilance on over loading and right powering, stalling has been reduced. This can be fully avoided if additional tractive power is provided between HX-NRE stations especially during rainy season.

(iv) Scabbing : Scabbing is mostly found on rising gradient, signal

approaches and where trains speed is restricted due to caution order or other reasons. The comparative details of scabbing are given below:

Section 06-07 07-08 08-09 09-10 (Up to SEP’09)

BAY-GTL 0 0 1 0

GTL-RU 3 1 1 0

GTL-DHNE-NDL 13 3 0 4

In GTL-RU section the scabbing mostly has occurred in rising grade and in combination with insufficient tractive power at signal approaches and at caution order spots where driver could not regulate the speed in time. As regards GTL-NDL section they have mostly occurred in Ghat section where continuous rising gradient exists in uncompensated sharp curves in between PNM-KEF and in raising gradient between GTL-MKR stations. This can also be avoided by having sufficient tractive power and good engineman ship.