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Over Head Equipment – Cantilever

By on March 23, 2014

Cantilever hold the assembly of contact wire , catenary and dropper assembly. It transfers all vertical load, lateral forces and bending moment load through insulator to Mast. It is an insulated swiveling type structural member and keeps the overhead catenary system in a position assisting smooth current collection by the pantograph at the designed speed.  It is flexible with all joints having swiveling arrangement permitting movement in all direction.Material is so chosen to avoid any rusting and to last the life the OHE (35-40 years)

There are four tubes which makes the complete cantilever assembly namely

Stay Arm: It comprises of dia 28.4/33/7 mm (Small) size tube and an adjuster at the end to keep the bracket tube in position.  It is insulated from the mast by stay arm insulator.

Bracket Tube: It comprises of dia 40/49 mm (Small) or dia.  30/38 mm (standard) bracket tube and insulated by bracket insulator.  Catenary is supported from this member by catenary suspension brackets and catenary suspension clampCantilever Assembly

Register Arm: It comprises of dia 28.4×33.7 mm tube to register the contract wire in the desired position with the help of steady arm

Steady Arm: It is 32 x 31 mm BFB section made of aluminum alloy to register the contact wire to the required stagger and to take the push up of contact wire.  It is always in tension

Dropper is a fitting used in overhead equipment construction for supporting the contact wire from catenary.  Two top tubes hold the weight; adjust the height and center of the Contact and catenary wire assembly whereas the bottom two tubes for adjusting the contact wire – stagger/height.

Contact and catenary assembly is designed for following different applications namely, push, pull, overlapping, crossover etc. The arrangement of the cantilever depends upon the height of the contact wire, encumbrance, setting distance, stagger and super elevation.

Stay and Bracket tube is supported on the mast with the help of insulator for electrical isolation called Stay Tube Insulator and Bracket Insulator. Two standard sizes of tubes 38mm and 49mm outside diameter are used for bracket assembly depending on the loading condition. Bracket assembly permits adjustment of equipment to cater for slewing or raising of track during maintenance. Length of stay tube can be varied by as much as 9 cm. in either directions and bracket tube is provided with free length of 10 cm beyond the caternary suspension clamp. Similarly projection of the register arm beyond the steady tube clamp is kept at 15 cm. This makes it possible to adjust the stagger of OHE at later stage without much difficulty.

Most important feature of Cantilever assembly is its flexibility, swiveling in all direction to take care of vertical push during movement of pantograph and expansion during change of ambient temperature and Vertical and Horizontal adjustment.

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There Are 39 Comments

  1. nmr says:

    sir, gd mrg, the current collection video is very very good. And the articles on TRD OHE is easy to understand // thanx very much sir,
    pl provide an article on PT entanglement, remedial measures and 2 to 3 case studies..

  2. chaitanya says:

    Hello sir,i am OHE design enginer,General how we will decide drop arm implantation(i mean calculation)…?

  3. S rahman says:

    Single bracket/ cantilever assembly suitable for tramway type OHE including St by insulator

  4. atul Kumar vyas says:

    OHE supervisor

  5. Ranajit kumar Ghorai says:

    Pls explain me Span wise dropper length calculated formula (All Encumbrance)

    • Jagannath says:

      If you want know how much droppers provides between two mast?
      This is very easy, first you major the span between two mast then divide the span by 9 then + 1,
      Ex-if spn is 45 then 45(spn)/9=5(then +1)=6

    • Jagannath says:

      Which dropper is near from mast that is the A dropper, (we mention droppers like A dropper, B dropper, c dropper)
      A DROPPER distance 6.75 m, B dropper distance 4.45 m, c dropper 2m

  6. Pradeep kumar patel says:

    Good facility
    I am pradeep kumar patel
    Railway electrification Ohe line supervisor banana chahata hun

  7. Arun says:

    Very use full

  8. Siva says:

    Excellent please make to download in PDF format… Then it will be very helpful for learning…

  9. chandan says:

    hello greeting of the nigt .
    I am railway contractor ,basically
    I want to assambeling the cantilever in western railway
    So will you providw the product to me

    • Mahesh Kumar Jain says:

      I am sorry. I don’t have information on this subject. You may visit RDSO/RE(core) website to get the information on the approved sources of cantilever assembly.

  10. muzaffar hussain says:

    Good morning sir, can you please give me the abbreviations of these terms used in designing and execution of Indian Railway Projects.
    Thanks sir.

    • Mahesh Kumar Jain says:

      PTW: Permit to Work; LOP: Layout Plan; SED: Structural Erected Design; ESP: Engineering Scale Plan; ACTM: AC Traction Manual; ODC: Over Dimensional Consignment; IOL: Insulated Overlap; UIOL: Uninsured Overlap; As regards other, I don’t have the information.

    • John says:

      RRA – Raised Register Arm, ACC – Anti Creep Centre, FTA – Fixed Termination Anchor, MRL – Main Rail Level

    • Prashanth says:

      MRL:- main rail leval

  11. Biraj Dahare says:

    Bracket fabrication and dropper making all completely work

  12. Suvasis says:

    St tube majerment system bol Denge to thora help hota

  13. Ibrahim Zafar says:

    Sir, explain me about 3 kV returning in traction electrification.

  14. Niraj kumarGupta says:

    Thank you sir

  15. Brijesh says:

    What materials 6351 ohe railway

  16. Susanta sadhu says:

    Learn design and drawing

  17. Veer says:

    Hi sir i want learn ohe work can you suggest me any book, video
    You tube Chanel.

  18. Vikas Yadav says:

    Vikas Yadav

  19. Nitin Sharma says:

    We have an Urgent opening of Sr Purchase Engineer for one of the leading Manufacturing Industry.

    Position : Sr. Purchase Engineer
    Company : Manufacturing OHE Railway
    Location : MP
    Salary : 5-7 Lacs

    Interested Candidate Contact Nitin Sharma 9810956473

  20. Prashanth says:

    MRL:- main rail leval

  21. Sandeep says:

    Sir, I am a SSE in ELectrical-G dept, am preparing for my AEE LDCE 30%. To qualify in paper-I I need some electrical material, so sir can you suggest me some website in which I can get all the syllabus materials easily . I shall be very much thanksfull for this.

  22. Sharik khan says:

    Sir, I want to about ,how Cantilevers assembled as, below
    Then, what length stay tube, what length bracket tube,and what length registered tube,
    What formula ,
    So please send me mail id

  23. Sreekumar says:

    I am looking for buying BFB steady arm and related materials,can any one advise a supplier?,Thanks.

  24. Suman says:


  25. Rohit kumar says:

    Ohe ke object question answer

  26. K.Kudhaf says:

    I like these concept answers in OHE in traction

  27. MD basheer ahmed says:

    Related videos to be posted clearly for easy understanding.