CTR and TGI Value

CTR ( Rly. Bd. Letter 90/Track-III/TK/72 dt. 18.7.90)

CTR=100-(ULA+URA+TA+GA+ALB+ARB)

Rev. CTR (item 840 of 66th TSC)

RCTR=100-(ULB+URB+TB+GB+0.5ALB+0.5ARB) -0.25(ULA+URA+TA+GA)

TQI ( RDSO Report no. C-223)

TQI=8(U2+2T+G+A)

TGI ( Rly. Bd. Letter 94/Track-III/TK/23 dt. 25/31.08.95)

TGI(for a block) =(2UI+TI+GI+6AI)/10

TGI for a KM = (Sum of TGI of all blocks) / No. of blocks

UI=100e-(SDUm-SDUr)/(SDUur-SDUr)

SDUm=(SDU2l+SDU2r)/2

TI=100e-(SDTm-SDTr)/(SDTur-SDTr)

GI=100e-(SDGm-SDGr)/(SDGur-SDGr)

AI=100e-(SDAm-SDAr)/(SDAur-SDAr)

SDAm=(SDA1l+SDA1r)/2

Maintenance Guidance using TGI Values

As per Rly. Bd.’s letter Dated 30.12.96

Features of TGI

• Tool for monitoring track laying standards

• Tool for deciding maintenance

• Continuity with existing practice

• Proper appreciation of maintenance effort

• Good correlation with Ride Index Values

• Proper range of values

• Reasonable variation in values

Limitation of TGI

1. Combination of all parameters makes it redundant for showing maintenance.

2. For maintenance individual index should be considered.

3. Range is narrow for poor and consistent good track.

4. Range is proper for entire variation.

5. TGI don’t indicate speed restriction.

6. After change in Track standards, TGI can be improved.

Action to improve TGI

Following items should be attended to improve TGI value of track in a section:

1. Alignment survey and correction specially on short chord.

2. Unevenness is corrected for left and right rail separately.

3. Rehabilitation of weak formation should be planned and work should be carried out on programmed basis.

4. Attention of fish plated joint as required, including Buffer rail and SEJ.

5. Attention to transition length of curve.

6. Attention to approaches of LC, bridge, points & crossing.

7. Attention to pumping & blowing joints.

8. Providing clean ballast cushions.

9. Replacement of pitted rails and wheel burns etc.