Erection Traveller (Crane used for high level bridge)

[Rayman4449]

From the Lethbridge Historical Society:

 

The Erection Traveller, usually simply called the Traveller, is arguably the most incredible machine ever used in Lethbridge. This was the machine that set the steel into place for the High Level Bridge.

* 11 miles (17 km) of cable for raising and lowering
* weighed 712,000 pounds (approx. 322,000 kg)
* took a month to build
* cost $100,000 in 1908 (approximately $2.5 million in today’s terms)
* traveller sat/moved on the top cover plate of the girder spans and stood high enough that locomotives and loaded railcars could go beneath it
* took 10 months for the steel to be placed on the bridge (August 1908 to June 1909)

The stats and statements above provide a little bit of information on the Traveller but the quote below (from Alex Johnston’s book on the bridge) provides detailed information on how the traveller operated and all of the aspects of the job of getting the machine to work and putting the steel in place:

“For the first three spans of the bridge, wooden false-work was constructed and a small traveller, built on a 130,000-lb railway car, placed the steel. The device, essentially a small travelling crane, was then used to build a much larger crane, sometimes called the erection traveller or, more often, simply the traveller. The erection traveller was a very ponderous machine, built entirely of steel, except for some minor parts such as the engine-room floor, engine-house, and the various platforms. It was made up of two principal trusses 207 feet long, spaced 16 feet apart, so as to conform to the spacing of the main girders of the span. The cantilever portion of the trusses had a reach of 116 feet, and the balancing portion, 91 feet. The rear end of the balancing arm was carried on three 24-inch cast steel wheels on each side and the forward end on four such wheels. The balancing arm was counter-weighted with 30 tons of steel rails in addition to the weight of the engines and hosting machinery. According to news reports, the main boom was capable of lifting 50 tons and, to balance, the whole machine when it was extended with this weight, workmen placed 56 tons of steel on the traveller’s body. Special runways of oak plank, with 80-lb rail on top, framed to fit over the top cover plate of the girder spans, were bolted together in section for easy movement after each movement of the traveller. The weight of the traveller in working condition was 712,000 pounds. It stood 60 feet high on completion, took one month to build, and cost $100,000.

There were installed on the traveller two 80 HP boilers and six hoisting engines, One of the latter was a special 12-in x 14-in engine, designed to hoist the maximum of structural steel of 30,000 pounds. Eleven miles of cable were required for lowering and raising the column material.

The clearance under the deck of the traveller was sufficient to permit the passage of loaded flat cars. The steel girders were picked off the flat cars with the aid of 40-ton hydraulic jacks, run forward into position, then swung out and lowered into place with the aid of manila rope tackles. Lighter material, such as longitudinal and transverse bracing, was unloaded by wire-rope tackles attached to the trolleys, then lowered directly to the ground. For the raising of longitudinal bracing into final position, the traveller was equipped with two 85-foot swinging booms of five-tin capacity each.

To erect the bents the traveller was moved into position to bring the hoisting tackles at the end of the cantilever directly over the centre line of the bent to be erected., the overhang of the traveller being sufficient to span the maximum space of 100 feet. Upon completion of the lower storey of a bent supporting a 100 foot span, the top was braced back to the previous tower by a 100-foot long temporary strut. Similar struts were placed as each storey was erected so that, upon completion of the bent, it was in a condition to receive the 100-=foot long girders and to sustain the weight of the traveller when it was moved out to the position required for the erection of the 2nd bent necessary to complete the tower. These temporary struts remained in place until the 2nd bent of that tower was fully in place and secured. Tower bents were spaced 67 feet 3 inches, centre to centre with a similar length 8 foot high girder beams.

As the second bent of each tower was built, permanent longitudinal and diagonal bracing were put in place. Two assembling cages were used ot provide for the safety and convenience of the workmen, one on either outside of the structure. These were put in place by the 85-foot booms and were temporarily bolted to the steel columns and raised as each tier of the towers were assembled. Ladders enabled workmen to reach all points requiring erection bolts….

A novel device was the assembling cage used for the erection of the transverse bracing of the bents. It was suspended from the forward end of the erection traveller and consisted of a light steel frame with bottom, intermediate, and upper platforms, giving simultaneous access to all the joints on any one storey of the transverse bracing. The lower platform was 111 feet in length, on account of the great width of the bents, and it was 47 feet high. The three platforms were connected by ladders and a telephone enclosure (booth) for wind protection was installed in the centre. The telephone operator, who was constantly in touch with hoisting engineer operators, was in a position to see all the work in progress….

The assembling cage platform was used to side-haul the column sections. Ordinarily this work was done from ground station winches placed at a distance from the base of the towers. Tackles were connected at each end of the assembling cage, with cables running to one of the hoisting engines.

The platform was lashed to the columns by ropes in order to keep the assembling cage steady in high winds.

A riveting traveller was constructed of wood and ran on the same track as the erection traveller. It, too, was built high enough so that loaded flat cars and a locomotive could pass beneath it. Riveting cages were suspending from the overhang of this traveller. These consisted of a long platform or gallery on each side of the structure and small cages that could be raised and lowered independently. Compressed air at 100 psi was piped from a compressor plant at the east abutment to the riveting traveller, then by flexible hoses down to the workers.†(Canadian Pacific Railway High Level Bridge at Lethbridge written by Dr. Alex Johnston, published by Lethbridge Historical Society)

The Traveller was used on other projects after the High Level Bridge but its history after Lethbridge does not seem to be as well documented as its time spent building our bridge.

 

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[Rayman4449]

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[dieseldude]

Cool!  Wouldn't that look impressive on your layout!!!

 

 

-Kevin.

[enginear joe]

Fantastic!

Love the engineering behind some of the fabulous stuff that was built back in the day. Mind bogeling to think what they attempted for their time. No wonder our nation became such a power.

[Rayman4449]

Totally agree!  And thought the same thing that this was a fantastic piece of engineering

[Allen Rardin]

someone did make a model (HO gauge) of the traveller way back when.  check the nmra bulletin perhaps 20 years or so ago.  plans to make the model were the actual plans that were donated to a museum.

[Screwy Nick]

Thank you for reviving this.  I never knew anything like that ever existed, great engineering and yes would make a beautiful item somewhere near the end of they layout eluding to further construction.   

[Sean]

That is a fantastic piece of equipment ..thanks for posting that ..