Tag Archives: hydrostatic test

Greetings from the Mid-Continent Steam Team

Mid-Continent Railway Museum Posted on by

On July 20th Mike W., Pete D., Ed R., Mary S., Andy S. gathered at 8:00 AM to perform the first hydro test on the Chicago and North Western #1385 locomotive after all the studs and appliances have been added to the boiler. This is our own test to make sure that we have no leaks before the Federal Railroad Administration (FRA) witnessed test. We were able to get the boiler up to 90 degrees with a propane fired heater and a heated power washer. We slowly pressurized the boiler to around 125 PSI. The operating pressure of the boiler will be 200 PSI. This gave us a list of only a few items needing to be addressed before we perform our next test. 

All washout plugs were found to be leaking as we found the sealing surfaces improperly seating.  The sealing surface of the plugs are in the process of being trued up on the lathe now and the sealing surface of the sleeves will also be touched up. We have 2 staybolts that were found to be leaking and will be replaced very soon. We also had a small drip where the superheater header mounts to the front flue sheet, so the superheater units have been removed for access. We found about 5 studs altogether that were weeping and will be tightened.

Overall, this first test went very well, and we had no major issues. Plans are in motion to address the items we have and will be looking at doing our next hydro mid to end of September. Once we are confident we have all the items addressed, we will bring the boiler slowly up to 200 PSI and not over 120 degrees Fahrenheit. Then we will hold it and if no leaks occur then we will be ready to schedule our FRA witnessed hydro inspection.

This has taken a tremendous amount of capital and volunteer hours to get to this point. We have come very far and have done something at Mid-Continent we have never done before, a total rebuild of a steam locomotive to FRA standards. We have learned a lot in the process so far and still have a way to go. Please help support this project with funding and general support of our steam team. Without everyone pulling together we would not be as close as we are. A big thank you to our team and all our members and railfans that have supported us! We will not let you down.

Thank you for your help and support.

Andy S.

President

Mid-Continent Railroad Museum

Please visit the Donations Page to make a contribution toward the 1385 or other museum projects.

Prior to the day of the test, C&NW #1385 was rolled out of the shop and filled with water. Jeff L. photo.
Pete D. calibrates the pressure gauge to be used for the hydro test. Jeff L. photo.
C&NW #1385’s first hydro test begins. Lindsay L. photo.
Ed R. regulates water flow from the pressure washer as the needle on the boiler’s pressure gauge begins to climb. Lindsay L. photo.
Mike W. and Andy S. inspect for signs of leaks in the firebox. Jeff L. photo.
Mary S. monitors water flow. Andy S. photo.
The boiler pressure gauge shows just under 100 PSI as the team gradually ramps up the pressure. Ed R. photo.
Ed R. and Pete D. take notes on the leak locations and begin planning the work ahead. Andy S. photo.

C&NW 1385 Boiler Passes Hydro Test

Mid-Continent Railway Museum Posted on by

This is our 100th C&NW #1385 steam status update posted to our website and it is a momentous one! The locomotive’s new boiler has passed its hydrostatic test (a.k.a. hydro test). This test affirms the new boiler remains sealed with no leaks while at pressures well in excess of its designed operating pressure.

Pressure gauge showing 300 PSI during 1385’s hydro test. Photo courtesy Continental Fabricators.

This test is conducted by filling the boiler to the point there is no (or practically no) air trapped in the boiler.  Additional water is then pumped in until it reaches the designated test pressure – this can require as little as a few cups of water.  Excluding the air allows the boiler and appurtenances to be safely tested for. If a leak appears the pressure quickly drops by relieving that cup or two of water.

To complete the test, the boiler is then left under pressure for a period of time. An inspector then checks to see if the pressure has dropped. If the pressure has gone down more than a few percentage points, it indicates a significant leak which must be tracked down and corrected. If the pressure does not see a drop by more than a few percentage points, it indicates there are no significant leaks and it passes the test.

The 300 PSI you see on the pressure gauge is 1 ½ times the designed maximum working pressure of the boiler. This is one standard benchmark percentage for testing and helps prove the boiler has a margin of safety when in use.  The 1385’s boiler has been designed for a maximum allowable working pressure (MAWP) of 200 PSI with a minimum safety factor of four.  This means the boiler is designed to withstand pressures of at least four times greater than the MAWP which you can see gives a sizable margin of safety when in use.  The 200-pound pressure also marks a return to the R-1 class locomotives’ design pressure, meaning the engine will be restored to its original capabilities.

 

Up next: Prepare and attach the smokebox and paint the boiler exterior.