Gaging Resources


Below are the forms needed to submit gaging device and rod replacement orders. Please download the appropriate form, complete in full and then submit, along with your PO, to your Customer Service representative.


  1. Is it an industry practice to use these devices for weight calculations and ultimately billing? Also are they considered accurate enough for billing purposes?
  2. Midland’s B-612 Magnetic Gaging Devices are mainly used for level monitoring while loading the car with the commodity to prevent overfilling the tank car. The level reading they provide can be used as a reference, but most of the tank car operators use other methods for billing purposes, such as calibrated meters or calibrated weigh scales

  3. What is the accuracy of the devices (expected variance)?
  4. Midland’s B-612 Magnetic Gaging Devices provide a reading accuracy of ± 1/8”. Our gage rods are marked with tapes that have ¼” increments.

  5. How often should these be “looked at” and/or replaced?
  6. Midland’s B-612 Magnetic Gaging Devices are designed for long life, but operating conditions vary which affects the life of the device. Many of Midland’s customers currently have devices that have been in non-aggressive service for several decades. If all the components are in good operating condition (no leaks or physical damage), and if the magnetic coupling between the float magnet and the gage rod magnet has not been compromised, the device does not need to be replaced.

  7. What is the life expectancy of a Midland device?
  8. Midland warrants Gaging Devices to be free of defects in material and workmanship for a period of one year from date of invoice. However, Midland Gaging Devices are designed to last for several years without issue. Actual product life truly depends on the environmental conditions and proper handling.

  9. How difficult is it to replace the rods?
  10. It is very easy to replace a gage rod. All that is needed is a serial number that is stenciled on a flange of the gaging device housing and printed on a gage rod label (if the old rod is available). The serial number will provide the information needed to design an exact duplicate gage rod (“in kind”). Preferably, it is ideal to provide the serial number, specific gravity, commodity and car number (for reference purposes). If the serial is unavailable, one of our replacement gage rod forms will need to be filled out (Form 5 or 6). These forms can be found in the Forms section.

  11. What are the differences between the 3 different replacement gaging forms? Which one should I use to replace a device or rod?
  12. Form 4 is required when a full device is needed. The data required is for the manufacturing of a full device. Form 5 is required when replacing an existing rod (or “replacing in kind”). The customer will supply the dimensions of the rod. No specific gravity and commodity will be displayed on the label of the replacement rod. This rod will be made to the customer dimensions only and is not calibrated to any specific gravity.

    Form 6 is required when replacing a rod with a different commodity or specific gravity and when a serial number is not available to calibrate the rod accordingly. This form is also useful when you don't have any information at all to start with. To fill out Form 6, the customer must remove the pressure plate to view the float specifications.

PLEASE NOTE that only one form needs to be used for ordering a replacement gage rod or device.


Midland Gaging Devices are the industry standard, with over 40,000 currently in use, providing accurate level monitoring and assuring complete loading and unloading of liquids. The devices’ small mounting flange size reduces space requirements, making it easier to locate other equipment on the manway plate and allow for emergency capping. Our 40+ years of historical data assures precise replacement of older parts, avoiding recalibration or replacement of the entire Gaging Device. Plus, you can retrofit existing Gaging Devices with a Midland Tank Car Loading System to maintain optimum load levels while reducing required fill time and allow remote liquid level management.

Midland Gaging Devices feature superior component engineering, resulting in long, carefree, accurate operation. Graphite rods, a stainless steel specific gravity correction nut and cap, and zinc-plated body and flange all contribute to delivering long-term resistance to corrosion and fast, easy gage reading. Various sizes of lightweight floats provide superior reliability and accuracy with low specific gravity applications such as LPG or Butane.