I-Beam load capacity question, what beam for 70 tons?

[gwrassiniboia]

Hi,
I'm sorry if there have been loads of posts about this, but I'm hoping someone can help me out here.

I'm making a pit to service a locomotive, this pit needs to be 10 feet wide (width along the rails), inorder to support the weight of the locomotive we have decided to run I-Beams under the rail to help the rail carry the weight. The weights distributed along the rails are as follows:

Each locomotive has 2 trucks, each truck has two axles, each axle has a weight load of 35 tons (appx 70,000 lbs).
The pit will only be wide enough for one truck, but two axles.
< 10' of I-Beam and Rail >
=====================
: ^~~~~~~~~~~~~~^~:
:~points where weight will~:
:~be resting ~~~~~~~~~:

(sorry for the crude picture)
The weight of the axles will rest on the outer edges of the beam for the most of the time, but we will need to drive over the middle of the beam at a very slow speed, so for it to hold the weight is critical (sometimes we'll need someone in the pit while the locomotive is moving).

What I'm looking for is what I-beam would be suitable, deflection must be less than 1 inch.
Any help with this would be greatly appreciated.

 

[russ_watters]

It is illegal for you to do this sort of construction work without the assistance of a registered professional engineer and it would be illegal for anyone on this site to help you off-the-cuff.

Hire a professional structural engineer.

Thread locked.

 

[oswaler]

Based on the information provided, it is important to consider several factors when determining the appropriate I-beam for this application. These factors include the weight load, the span of the beam, and the desired deflection limit.

To support a weight of 70 tons, or 140,000 lbs, it is recommended to use a steel I-beam with a minimum yield strength of 50 ksi (kips per square inch). This will ensure that the beam can withstand the weight without significant deflection or failure.

The span of the beam, or the distance between supports, is also an important factor. In this case, the beam will only be supporting one truck, or half of the locomotive's weight. This means that the span will be shorter and can potentially allow for a smaller, lighter beam to be used.

Lastly, the desired deflection limit of less than 1 inch must also be considered. This means that the beam must have enough stiffness and strength to resist bending under the weight load and maintain its shape. The exact size and type of I-beam needed will depend on the specific dimensions and loading conditions of the pit and the locomotive.

In conclusion, it is recommended to consult with a structural engineer or use an online beam calculator to determine the appropriate I-beam size and type for this application. It is important to consider all the factors mentioned above to ensure the safety and stability of the pit and the locomotive.