At low speed and acceleration it's probably ok.
At high speed, please consider the following:
I'm going to make a couple assumptions and will speak to concepts because we only have a detail about the suspended mass:
- The hanging mass is hanging significantly far below the beam
- The hanging mass is rigidly connected to beam with 1 degree of freedom. (Not suspended by a cable or something which would make your mass a pendulum(think wrecking ball)
Moving a mass at significant speed is going to have momentum. When you start and stop the momentum you have an acceleration and deceleration.
Momentum = mass * velocity (for reference)
Force = mass * acceleration
Acceleration = (delta)speed/time
Torque or Moment = force*distance
So, if you significantly accelerate or decelerate your mass you have a high force. Multiply that force by the distance it's suspended from from the beam/track and now you have induced a moment load into the beam. This alone may be an issue for your beam. It may not.
Next, depending on the motion of your mass, for example if it moves only between two fixed locations, you might see fatigue at the two locations due to the cyclic or repeated stress at those same locations. If the mass can start and stop in any location along the beam it will have different implications. Also, you would need to calculate the combined load in the worst location(furthest point away from any supports.)
Last thoughts, the design of your "trolley" or skate which lets the mass slide along the beam could better distribute the load applied along the beam making it more capable to sustain the loads applied as described above.