I decided to make another eight-drive wheel locomotive. This time I would model it after the Pennsylvania Railroad's M1 4-8-2. Starting with a Gilbert K-5 boiler I had to stretch the fire box by about two inches. The boiler itself also had to be lengthened a little between the two domes. The feedwater heater behind the smokestack and the feedwater heater pump on the left side running board also had to be removed. The power reverse on the right side had to be moved forward a bit.

A running board had to be added above the air compressor on the left and the relocated power reverse and air reservoir on the right. I also added the exposed steam pipes on each side going to the cylinders. The K-5 had a cast frame and cylinder saddle that included the steam pipes internally.

Several different tenders were associated with this locomotive, including the type Gilbert modeled for the K-5. However, I thought I would try to model the big coast-to-coast tenders the Pennsy developed. To make this tender I had to cut up two Gilbert K-5 tenders. The final tender is pieced together from five pieces. I also added some skirting to make the tender look bulkier. The six-wheel trucks are from American Models.

Three more views of the Pennsy M1. These show the pilot deck with the air reservoir and elevated deck I made to simulate the same features on the real locomotive.

I also had to make an exposed dry pipe for the top of the firebox. The real locomotives had this feature on the M1.

The tender had the water tank and the coal bin both extended by about an inch and a half each. I used plaster to make the coal pile look smooth then added scale coal after the tender was painted and lettered.

The handrails on the real locomotive were not straight but were higher in the middle sections where the running boards were raised above the pumps and power reverse.

A close-up view of the joint where I joined two six-wheel frames to make the longer eight-wheel frame. The joint is a tongue and groove made from the gear well of the leading frame (groove) and a narrowed section of the second frame (tongue) to fit inside the gear well. This method has worked well on four of my locomotive conversions.

Two views of the boiler pieces and the copper pipe I modified to hold it all together. The fully assembled frame with smoke unit and can motor are in the rear.

The copper pipe holds the pieces of cast boiler in place and lined up.

Two views of the assembled boiler. I use J.B. Weld to "glue" the pieces together. It sets fast and is very strong. It also adheres to the metal very well. The picture showing the inside of the boiler also shows the two mounting posts I made to mesh with the rear mounting grooves on the frame. The original mounting posts with the metal tabs used by Gilbert did not line up correctly after the boiler and firebox were lengthened.

Two pictures of the assembled boiler being test fitted on the frame. I had to check to ensure the boiler sat level on the frame. These pictures also show the brass strips I used to fill in the gaps on the running boards and skirting below the running boards.

These two pictures show the locomotive and tender being tested for operation on my layout. The gaps in the boiler are filled with Bondo and modeling putty.

You can see the five sections used to assemble the tender. The skirting used to give the tender bulk has not yet been installed. The white stuff in the coal bin is the plaster I used to give the appearance of a uniform coal pile. It was later sanded, painted and had scale coal glued on it.