Mike's Workshop Notebook

Mogul Rebuild

Repairs, Changes, replacements and improvements made.

Photos

Old Mogul.
The locomotive before rebuild.
balsa replaced
The original red-dyed balsa molding was removed and replaced with brass molding, and a brass smokebox ring was added for appearance. The boiler was cleaned and painted with rust resistant paint. New boiler insulation was installed, and the jacket, smokebox, and cab were carefully repainted. The side rods and valve gear were removed, thoroughly cleaned, and nickel plated. This not only improved their appearance but also enhanced corrosion resistance and long-term durability.
Lubricator Choice
Two lubricator configurations were considered for this installation. One mounts above the running board, while the other installs beneath it. After reviewing the available space and mechanical layout, I chose the top-mounted lubricator to eliminate any potential interference with the valve gear.
Lubricator linkage
New Lubricator Linkage.
New Lubricator, New Rings
New Lubricator Installed.
Smokebox
The throttle valve was replaced, and the throttle linkage was redesigned to provide a smoother action and a broader, more controllable operating range. The blast nozzle was remachined to accept interchangeable screw-in nozzles, allowing for future adjustments if needed. New piston rings and gaskets were installed to ensure proper sealing and dependable performance under steam. The original head and valve body screws were replaced with steel socket head cap screws for improved strength and a more serviceable assembly.
Mogul Wrench
A dedicated steam gland packing wrench was required for proper adjustment and maintenance, so one was fabricated for the task. A prototype was first designed and 3D printed (left) to check size and clearances. Once proven, a metal wrench (right) was fabricated to the proven diminsions.
throttle linkage and blast nozzle wrench pic
The throttle valve plate (left), a key part of the redesigned Throttle Linkage was one of the first projects machined on my CNC setup. A fabricated Blast nozzle wrench used for swapping out screw-in nozzles. Custom Nozzles can be fabricated to control and tune the boiler's draft through the coal grate.
Whistle
The whistle bowl was misaligned and loose, so it was remachined to correct the dimensional discrepancy. Careful rework restored proper concentricity and seating, bringing the geometry back into alignment, making for a noticeably cleaner, more responsive whistle tone under steam.
Cabin
The throttle valve sleeve was replaced to restore proper fit and sealing. The bell ringer assembly was also replaced, and a speed control was added to allow an adjustable ring rate. The original incandescent headlight was upgraded to an LED unit, providing significantly improved brightness. New grates were installed as well.
Cabin
The new grate components were fabricated from high nickel-content stainless steel to provide improved heat resistance and durability. Inconel was considered, but ultimately ruled out due to cost. The two rectangular pieces with the half-moon cutouts were part of the fixturing used to hold the spacers during milling to final thickness. Maintaining a precise overall stack-up width was critical, as the assembled grate needed a snug, accurate fit within the locomotive’s grate support channels.
Cabin
Grates are considered consumable components on a locomotive, but the originals failed prematurely when a large chunk of anthracite coal made its way into the firebox and created excessive localized heat. To improve durability, the replacements were fabricated from a higher temperature–rated steel.
Tender
The Tender received a comprehensive refresh. A new Coal Bin was built, the wheel bearings and springs were replaced, a Hand Pump was installed, the water Tank Resealed, and the tender repainted
Coal Bin
The new TIG Welded Aluminum Coal Bin. (The discs are felt to provide a snug, rattle free fit in the tender.
New Loco
Finished