Portable Gauge measuring Railway trolley -- 2

I am looking for a freelancer to create a portable gauge for measuring the distance between rails on a railway trolley. The gauge should be lightweight and easy to carry, but lightweight and easily portable design. I prefer the gauge to be made of metal. The primary purpose of the gauge is to measure the distance between rails accurately. Ideal skills and experience for this job include:
- Experience in designing and developing portable gauges
- Knowledge of railway measurements and gauging
- Expertise in working with metal materials
- Ability to create a lightweight and easily portable design
- Attention to detail and accuracy.