Spring failures in trains can occur due to material defects, metallurgical issues, or improper assembly. Common causes include lack of parallelism or squareness in springs, which affects how axial force is transferred. Biting, where coils contact each other, can cause breakage. Proper inspection and maintenance of parameters like stiffness, deflection, and end tapers is needed. Standards for suspension spring properties in WAP-4 and WAG-7 trains are provided. Testing data on springs removed from trains confirms dimensions and loads. Past failure rates of primary and secondary springs are reported.

2. Spring Failure In Train
Submitted To:
Mr. R.V Singh Yadav
Submitted By :
 Anuvrat Shukla
 Sachin Awasthi
 Bhirendra Singh
 Rishabh Sharma
 Shyam Dayal
 Sanjay Singh

3. Types of Springs in Loco
WAG 7:-
1. Inner Spring
2. Outer Spring
WAP 4:-
1. Primary Spring
2. Secondary Spring

4. (A) Material failure(Dimensional)-
 Parallelism.
 Squareness.
 Biting Effect.
(B) Metallurgical.
(C) Improper Critical Parameters during assembly: - It is
observed that the failures occurs due to bad maintenance
practices in respect of improper critical parameters.
Causes Of Spring Failures

5.  Spring squareness is the angular difference between
the outermost limit of a spring diameter when
compared to a straightedge at a right angle to a
horizontal flat plate on which the spring is standing.
 This affects how the axial force produced by the
spring can be transferred to adjacent parts in a
mechanism.
Spring Squareness

6.  Spring parallelism relates to the ends of the spring
and how parallel they are to one another.
 A compression spring cannot be closed and ground so
consistently that its ends will always be square (in
parallel planes at right angles to its axis).
Spring Parallelism

7.  Spring should be checked properly for its Parallelism
Squareness & 75% tapered area and a gap of minimum
1.0 mm between effective coil and tapered end coil.
 If there is no gap between effective coil and tapered
end coil then the biting effect will take place and the
spring will be break at that point.
Biting Effect

8. The following parameters should be ensuring
before putting the spring in the system to avoid
breakage.
(i) Free height, working height.
(ii) Stiffness and Deflection
(iii) Squareness.
(iv) Parallelism.
(v) End tapper. Where,
• Stiffness= Working load in kg/ Total
deflection=Kg/mm
• Deflection=Free Height-Working height in
mm.

9. The following precautions may be taken during
assembly of the springs in the bogie.
• Primary spring sheet of bogie frame to be checked for
any uneven surface and crackness.
• Primary spring sheet of axle box to checked for any
uneven surface and crackness.
• The squareness & surface finish of axle box crown also
to be ensured for nil gaps for proper fitment.
• Provision of polyurethane spring pad (Happy pad) to be
made at top & bottom side of the springs as
recommended by RDSO.

10. SPRING TESTING MACHINE
ELECTRIC LOCO SHED KANPUR

11. Standard Parameters of WAP-4 & WAG-7 Suspension spring
S.No. Parameters WAP-4 Primary
Sups. Springs
RDSO Drg
No.SKDL-3472.
WAP-4 Secondary
Sups. Springs
RDSO Drg
No.SKDL-3473.
WAG-7,Outer
Spring RDSO
Drg.No.SK-VL-
039
WAG-7,Inner
Spring RDSO
Drg.No.SK-VL-
037
1. Free Height 385+6_6mm 478+7-7 mm 552+9-9 mm 512+9-9mm
2. Working
Height
320 399 447 402
3. Solid
Height
267.3 345.8 364 327.5
4. Working
load in kg.
3695 4110 4284 1700
5. Outer Dia. 178 210+1.5-1.5 mm 240 154
6. Inner dia. 112 134+1.5-1.5mm 160 104
7. Wire dia. 33 38+.10-.10mm 40 25
8. Variation in
wire dia.
+ -0.1mm + -0.1mm + -0.1mm + -0.1mm
9. Variation in
coil dia.
+ -1.5mm + -1.5mm + -1.5mm + -1.5mm
10. No. of turns 8.5 9.5 13.5 9.5
11. Wound RH RH RH LH
12. Out of
squareness
3.8 mm max. 4.8 mm max. 5.5 mm max. 5.1 mm max.
13. Parallelism 2.7mm max. 3.2 mm max. 3.8mm max 2.4mm max
14. Stiffness
kg/mm
16.77 to
20.29kg/mm
49.59 to 54.82
kg/mm
21 To28 kg/mm 57 to 73 kg/mm
15. loaded
height
316 to 323 mm 394 to 403 mm 441to 451mm 396 to 406mm

13. WAG-7 (Inner Spring) Dated:- 25-06-15
Sr
No.
MAKES YEARS FREE HEIGHT DIG.
HEIGHT
LOADING
FREE HEIGHT
LOADING
DIG.
1 GBD 01-14 515 514.4 401 400.6
2 GBD 08-13 518 518.5 397 397.0
3 GBD 01-14 513 513.6 392 392.3
4 GBD 01-14 513 517.8 396 395.0
5 GBD 01-14 513 512.2 408 407.8
6 GBD 01-14 513 512.2 392 391.4
7 GBD 01-14 517 516.7 396 396.6
8 GBD 01-14 512 510.8 396 395.7
9 GBD 01-14 515 514.3 393 392.4
10 GBD 01-14 512 511.4 397 396.3
11 FSK 05-07 513 512.4 416 417.0
12 AFJ 06-08 517 516.0 408 408.6
13 GBD 12-05 511 510.7 396 395.8
14 GBD 12-05 516 514.8 396 395.8

14. WAG-7(Outer Spring) Dated:- 24-06-15
Sr No. MAKES YEARS FREE
HEIGHT
DIG.HEIGHT LOADING FREE
HEIGHT
LOADING DIG.
1 AFJ 10-12 556 557.7 441 441.2
2 AFJ 10-12 556 556.0 438 436.9
3 AFJ 10-12 557 557.1 441 440.3
4 AFJ 10-12 557 556.9 460 461.1
5 AFJ 10-12 563 562.6 455 450.9
6 FSK 08-07 560 560.4 446 445.0
7 FSK 02-06 555 555.0 458 457.9
8 AFJ 10-12 558 557.4 443 442.4
9 AFJ 10-12 555 555.5 441 439.7
10 FSK 03-07 555 555.1 449 448.9
11 GBD 09-12 552 551.9 438 437.8
12 FSK 02-07 556 555.4 444 449.1
13 FSK 01-07 561 560.4 454 455.1
14 GBD 09-05 554 554.3 446 447.8

15. Sr No. MAKE & YEAR FREE HEIGHT LOADED HEIGHT
Analog Gauge Digital Gauge Analog Gauge Digital gauge
1 AFJ: 12-11 521 521.6 404 405.8
2 CSN: 06-97 519 520.2 400 401.4
3 CSN: 12-97 519 519 404 404.9
4 FSK: 12-10 523 523.9 409 408.7
5 CSN: 10-98 515 514.9 394 395.2
6 GBD: 07-09 521 521.7 402 402.8
7 CSN: 04-99 516 517.1 391 392.2
8 CSN: 11-98 523 522.2 409 408.8
9 CSN: 05-01 519 517.9 402 401.8
10 FSK: 07-07 520 520.8 408 409.2
11 CSN: 11-00 519 518.8 404 404.6
12 CSN: 06-97 519 520.2 404 405.9
13 CSN: 12-97 516 517.3 409 410.2
14 CSN: 02-95 521 522.3 408 408.8
15 FSK: 06-08 519 519.6 404 405.3
Testing Of Inner Spring (WAG-7) Dated:-16-01-15

16. Sr No. MAKES YEARS FREE HEIGHT DIG. HEIGHT LOADING FREE
HEIGHT
LOADING
DIG.
1 FSK 07-12 390 390.3 324 324.7
2 GBD 05-14 394 395.3 334 335.4
3 GBD 05-14 393 394.3 324 323.8
4 GBD 05-14 396 397.2 328 328.6
5 GBD 05-14 396 397.2 327 328.2
6 GBD 05-14 395 395.5 329 328.9
7 GBD 09-13 388 388.6 331 331.3
8 GBD 09-13 388 388.8 322 322.5
9 GBD 09-12 392 393.4 323 322.5
10 FSK 12-11 386 386.7 317 316.6
11 GBD 05-14 394 394.8 329 329.5
12 FSK 08-11 388 387.1 320 320.4
13 GBD 09-13 391 391.9 334 333.6
14 GBD 05-14 395 396.4 334 333.7
15 GBD 09-13 389 388.2 317 316.9
16 GBD 09-13 390 389.5 328 328.0
WAP-4 (Primary Spring) Dated:-30-06-15

17. Four years details of failure / breakage of Primary & Secondary Suspension Springs,
etc are as under.
S.No. Name of Equipment 2009-10 2010-11 2011-12 2012-13
1. Primary Spring of WAP-4 21 02 POH=03 NIL
2. Secondary Spring of WAP-4 04 Nil 01 NIL
3. Primary Suspension Spring of WAG-
7(Outer/Inner)
11 07 05 NIL
4. Breakage of Bolster of WAP-4 03 06 02=POH =01
AOH=01
01
5. Breakage of Connection straps. 12 12 POH=04 NIL

18. References
• I prepared this report from the various study materials
provided by the staff officials.
• Study materials and entire technical parameters of the
subject item provided by Mr. R.V. Singh Sir.
• Entire aspects and critical parameters of the spring are
got available by Mr. R.V. Singh. Sir, Once again I would like
to thank all the staff officials for their support and
helping us in our project throughout our training period.
• We are very Thankful to Mr. SANJAY SINGH Sr.DEE/RS for
giving us an Opportunity to complete our Summer
Training at Electric Loco Shed Kanpur.