Modifications to an ARM D55 to Improve Traction

I had not paid much attention to the D55 class as a model as they were mostly outside my 1965 period for my layout but when Australian Railway Models produced the oil burner version of the D55 I still wasn't interested. However, one day on YouTube I came across the Graeme Belbin video below which got me thinking; here was a coal burning 5597 in 1965.

Here is the video by Graeme Belbin of 5597 on the 1965 Triple Headed Standard Goods Tour, Unanderra - Moss Vale:

Further searching came up with these photographs of 5597.

5597 Wollongong Station 1965-04-04 - Facebook - Brett Fitzpatrick

5597 at Thirroul Loco Depot RTM Kiama Tour - 23-10-1966 - Peter Neve

Of interest is this photo of 5597 in March 1965 with a Turret tender, it is apparent that the Wampu tender was put on 5597 for the 4 April 1965 tour. But, did it then have the Turret tender put back after the tour? And, was this repeated in October 1966?

5597 Moss Vale to Sydney New South Wales School Railway Clubs Association tour
 March 1965 - Laurie Anderson

So, I thought, why not?

I purchased an ARM D5502 model and proceeded to modify it to represent 5597 in April 1965 and October 1966 when being used on tours with a coal Wampu tender instead of the turret tender it was normally fitted with prior to that time.

The first thing I did was the hardest as I had to cut the oil tank out of the tender and the plastic was quite thick. I used a small thin stainless steel saw blade in a Dremel motor tool working very slowly and carefully along the tender side so as not to damage the flared tender top walls. The most dificult section was cutting out the rectangular protrusion of the tank through the bunker door area. Once again I used the small saw blade in the Dremel and finished with a hobby knife and files. I then did a 3D print of the coal doors based on a plan of a Turret tender as I had no photos, etc. of the Wampu doors.

I also did a 3D coal load thin base to cover the hole left after the oil tank was removed.

The observant will notice that I also did a 3D printed funnel. More on that later.

I also designed and printed some coupler boxes to take Kadee 144 Short Underset Whisker Standard Head Couplers. These coupler boxes replace the coupler covers that come on the D55. However, the hole in the Kadee coupler has to be carefully reamed or filed with a 'rat tail' file to just neatly fit on the existing coupler mounting post. Some Kadee 'Greasem' is a help here as well. The 3D printed coupler box has a short tapered arm that protrudes out the front under the coupler to support it. The coupler whiskers stick out but bear on the inside of the coupler box to give the centring action. The tightness of the screw that holds the coupler box is adjusted so that the coupler works as it should.

At this stage it was possible to test the pulling power of the D55. Disappointment!

I then began trying several different motors that I bought online. Finally deciding on a single ended shaft FF-050SK-11170 12v 16800 rpm DC motor obtained from AliExpress.

This motor was chosen as it was longer and hopefully had more torque, but it did require the front motor mount to be removed by a cutting disc then a grinding stone bit in the motor tool.

A Loksound 4 decoder wired with an 8 pin plug, a Keep Alive, and speaker were fitted in the tender.

As the D55 only picked up power from the locomotive driving wheels I added 0.8mm phosphor-bronze wire pickups to the tender bogies with 10BA washers and M1.4 4mm self tapping screws obtained from AliExpress. The following photos are self explanatory.

Now, the way that the D55 was wired was quite annoying so I opted to 'improve' it. As per the following photos I cut out the lower part of the rear of the cab and the 'under floor' to make a channel for the wiring to easily get to the 8 pin socket. This also makes it simple to remove the locomotive body.

The search now began to find places to add some lead weight.

The locomotive has had 0.8mm sheet lead fitted on the underside the cab roof, white metal driver and fireman, and a rolled 0.8mm lead sheet representing a canvas roll fitted to the rear of the roof for protection from the elements. The 0.8mm thick lead sheet is from some used lead window flashing I found years ago.

There are one and a half layers of 0.8mm lead in the underside of the cab roof, the half layer being at the front as it would show at the rear if it was a full layer. The canvas roll was scribed for some strap indentations and some brown paint in the grooves represents the straps. The canvas roll is important as the further back the weight is the more it will add weight to the drivers, think about lever action.

This 0.8mm lead is also fitted on both insides of the boiler and the inside top of the boiler in 65mm X 12mm pieces made very flat by squeezing in a smooth jaw vice. The extra weight is to try to overcome the incorrect placement of the metal weight in the smokebox which really only puts its weight primarily on the front driving wheels and probably lifts the rear drivers slightly..

At this point the D55 was assembled, painted and re-numbered to 5597.

Load Testing

I did some load testing on the 1 in 40 grades of the layout and here is a video of a trial with a load of LCH coal hoppers and guards van.

The 20 LCH coal hoppers are Eureka Models with the internal hopper weight and the plastic coal load. It should be noted that the LCHs are quite light weighing in at 23 grams. The SHG guards van is from SDS and it weighs 66 grams. The total weigh of the train is 526 grams.

If you stay to the end of the video you will see 5597 slip to a halt near the top of the final grade before the top staging yard. It appears that although I measured the risers and placed them within 1mm, the layout frame below at that point wasn't level so I seem to have a grade a bit steeper than 1 in 40. Investigation and hopefully a correction to be done.

Actual NSWGR D50, D53 and D55 locomotives were rated to haul only 12 LCH loaded hoppers and guards van on a 1 in 40 grade (310 tons).

Note: 5597 also slips to a halt at this place on the grade if pulling 12 LCH hoppers and the SHG van.

The track at the point of slippage may have a twist as it starts to go around the curve causing only three driving wheels to contact the rails. It is not likely that the prototypically correct flangeless middle drivers would contribute much traction.

I then tried 5597 with a load of 8 empty BCH and an MHG guards van, each BCH is 71 grams and the MHG is 75 grams for a total train weight of 643 grams. The eight BCH train is the length of coal trains that will fit in the coal mine on the layout. Note that the coal mine area is not complete as yet.

5597 with the BCH load slipped to a stop about 30cm short of the position that 5597 with the LCH load slipped. So, given that the actual weight of the BCH load was 117 grams heavier it does seem to point to a track issue at the final curve into the top staging.

In regard to operations on the layout, the coal mine branch is easily reached by both LCH and BCH train loads. The LCH train would be of empty hoppers, although the LCH hoppers will retain the grey weight.

In Conclusion

All up, I am reasonably happy with the modified 5597 and it will find a place in the Wollar Locomotive Depot where it can be called upon to haul the Down empty coal trains to the coal mine and will likely be called upon to be used as a banker to assist the heavy goods trains from Kerrabee to the top Gulgong staging. When using a banking locomotive at the rear of a goods train be aware that it should be a locomotive with poorer traction than the lead locomotive. It needs to be able to lift about the last third of the load. A locomotive at the rear that is too powerful can jack knife the train.

Note:

By all means, do the weight installs and change the funnel, etc. but perhaps leave the motor change until you have added the extra weight and then decide.

Download the 3D STL Print Files Here

I have made available on Thingiverse, some 3D STL files of a better oil version funnel with funnel cap, a pair of coupler boxes, and for those who may convert the D55 to coal, a coal version funnel, tender coal bunker doors and a coal load base to seal the area opened up by the removal of the oil tank.

5591 stored at Broadmeadow in August 1959 - Peter Neve

Close up view - 5591 stored at Broadmeadow in August 1959 - Peter Neve

3D Render of the oil version funnel STL print file

3D Render of the Coal version funnel STL print file

I have included STL files with supports, these printed on my Anycubic Photon Mono M5s 12K resin printer but STL files without the supports have also been included.

These STL files should only be printed on a resin printer.

Here is the link for the Thingiverse STL print files.

Enjoy!