K28 Tips

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The cunning plan with this page is to provide some hints and tips on the care and feeding of your K28. Its the sort of page that will evolve as our collective experience of the models grows. I'll start it off but you are encouraged to join in with things you learn on the way.
 
 

Please remember this is a work in progress
  User Manual / Instruction
  It doesn't come with one. I agree that's crap but PSC / MMI seem to think you are all genius's and don't need one. I have suggested to them that this is unacceptable if they are aiming to take their products to the mass market.

I suggest that if you think they should you let them know your views
 
  Getting in the loco body
 

       To disassemble the loco follow this procedure. All the pictures in this section enlarge if clicked

Unclip the lower end of the cab handrails from the chassis. I forgot to take the picture until after it was apart.

With the loco on its side unclip the reach rod from the top of the lifting link [in non technical speak unclip the fork end of the long rod coming from the cab from the sticky up bit of the valve gear]         <click here for reach rod info>

Tip the loco up side down in a foam support to hold it firmly but safely.

Remove the two screws under the rear of the cab and above the trailing truck. The truck will swing out of the way to let you at them.

Remove the pony truck – watch for the washer above and below the truck trace.

Undo the two very small screws, one either side of the representation of the equalising beam [the black wiggly bit revealed by removing the pony truck]

Remove the equalising beam casting; it hooks in near the front drivers. You have to wiggle it a bit.

Remove the big screw now revealed in the centre of the cylinder casting.

The body is not now fixed to the chassis. To part them imagine they are hinged at the rear and pull the cylinders away from the smokebox. Done like this the injector pipes fastened to the cab should untangle themselves

The body is still attached by two small plugs for the lighting circuits. Before you unplug these mark one either side of the plug with white paint or something. I used tipex.

Reassembly is the reverse of this procedure

 
  Access and lubrication diagrams from PSC
 

These three diagrams for the K28 have recently appeared on the PSC website. Click on them for the bigger picture

   

 
 
  What's in the little packets
  Taking one of the engines I've opened here as an example it came with three small bags of extras in it.
   
Bag1 - Nut Spinner

I haven't tried this yet but I suspect that its the right size for doing nuts on the end of the crankpins. From this you might have guessed I haven't had call to try to use it yet. A more useful tool would have been a screw driver to fit the really small screws you have to undo to take the body off.
Bag 2 - Odd Bits

This bag contained the following: -

4 Chains -  I guess these are safety chains that the prototypes had fitted between the tender trucks and the tender body. I would have expected 8, one for each corner of each truck but then I'm only guessing what they're for.

Spark Arrestor - This goes on top of the chimney. Looking at pictures I suspect they only used to put them on the engines at dry times when a spark could cause a fire.

Small PCB - Guessing again but this looks like the little circuit board that the K27's had in them to connect the rubbish should system to the cam. Its not needed for any of the proprietary sound systems you might be fitting.

3L brackets and Screws - Again going on what was actually fitted to the K27's these are fixing clamps for use in the tender to fasten the speaker down. They may be of use to you, it depends upon what speaker you decide to fit.

Anorexic Footplate Crew - A driver and fireman for your engine. They are the right size to fit on the seats but they are undersized for 1:48 scale people
Bag 3 - Fire Irons

These are a representation of the fire iron and shovel which to my eye appear as undersized as the crew supposed to use them. On your model you might see them resting on top of the coal or on the tender.

 
 
  Rear Coupler
 

It doesn't come with one!

For On30

For 0n30 use something like a Kadee #5 and use the middle of the three screws provided at the back of the tender. Take the outer ones out and save them somewhere safe. The floor height is set with the higher 0n3 couplers in mind so you will have to make spacers down to the right height from plasticard or similar.

For 0n3

Use a Kadee 803 using the outer screws to fix it, save the middle one safely. Again you may need to add plasticard spacers to get it down to the right height.

In both cases use a height gauge to ensure they're at the right height
 
  Wiring Diagram
  PSC have placed the wiring diagram for the engine on their website so I have copied it here.

One thing to remember is that the engine to tender drawbar is part of the electrical circuit as the loco is live to one rail and the tender is live to the other. The drawbar is insulated from the loco and takes one side of the power circuit from the tender to the motor in the loco.  This is common on US models and on brass models but not so common here in the UK

Click the picture for a bigger view
 
  Fitting DCC
 

The engine is DCC ready but in a slightly unusual way. Instead of the usual 8 pin NEM socket it is wired to a 9 pin JST socket which for DC operation comes plugged in to a little circuit board on the engine that connects it up for DC operation and has all the interference filters required.

The easiest way to convert the engine to DCC is to use a decoder that has the 9pin JST socket on its edge. Decoders like this are the: -

  • Lenz Gold

  • Digitrax DH123PS

  • Soundtraxx Tsunami

 These are just a few examples and not an exhaustive list. I have used the Lenz and Soundtraxx decoders.

To fit just a motor control decoder.

  1.  Remove the loco body – see instructions above

  2. Unplug the supplied JST 9 wire lead from your decoder and save it for another time.

  3. Unplug the JST plug on the engine from the small PCB in front of the motor. You can remove this PCB and put is away for if you need to convert the engine back later.

  4. Plug the engines JST plug into the socket of your decoder.

  5. Tuck the decoder out of the way securing it to the engine with tape or double sided sticky

                  Now all you have to do is program the loco. Remember, the engine gets its track power from one side of the loco and the other side of the tender. To run it without the tender touch the LHS wheels [or any part of the loco frames] of the loco with one wire and the tender drawbar with the other.

 To fit a Soundtraxx Tsunami Sound & Motor control decoder.   See Update Note Below

Fitting a sound decoder is a bit more involved, not because its fundamentally difficult, just because its a tight squeeze

  1. Remove the loco body – see instructions above

  2. Unplug the supplied JST 9 wire lead from your decoder and save it for another time.

  3. Unplug the JST plug on the engine from the small PCB in front of the motor. You can remove this PCB and put is away for if you need to convert the engine back later.

  4. Plug the engines JST plug into the socket of your decoder.

This leaves you with the three wires from the other end of the decoder to deal with. These are: -

  • The wire to the synchronising cam

  • Speaker wire 1

  • Speaker wire 2

  1. Take the tan wire and solder it to the top of the sound cam wiper just in front of the gearbox

  2. Run the two speaker wires out under the cab floor same as the back up light wires and solder one half of a 2 pin plug to the wires. Soundtraxx have a suitable plug and socket available.

  3. Tuck the decoder out of the way securing it to the engine with tape or double sided sticky

  4. That’s it for the loco – you may want to leave the body of until you have proved it working on the DCC programming and test track.

Update - it seems that with this engine and, possibly, the other MMI engines that there is an issue that the voltage dropping board in the loco takes too much current for it to be powered from a function output of the Tsunami decoder.

I wasn't aware of this as it is my normal routine to pretty much rewire the loco's anyway [see the lighting problem notes below]. I chuck the MMI voltage dropper away and wire the low voltage lights to the functions with suitable resistors. Doing this means you can put the marker lights and number board lights on separate functions.
 
  A Lighting Problem
  There has been a high incidence of wiring faults in the K28's I have worked on. The fault is that the holes in the boiler through which the low voltage lighting wires are pulled are a bit tight and there is a tendency to strip the insulation. The failure rate has been about 50% so after spending ages fault finding on the first two engines I have a policy of pulling new draw wires in with the original lamp wires and then using these to pull new lamps in with finer wire and a little Vaseline on the wires to ensure they go in without damage. In the long run its quicker, ensures I know the rating of the lamp and can wire it in with the resistors all at the same time
   
  Fitting The Speaker
  Fitting the speaker in the tender will follow shortly
 
  Engine - Tender Drawbar
  Coming Soon
 
  Rear Air Hose
 

  On the back of the engines tender there is a cast brass representation of the air hose. The cast brass is rigid and inflexible and, as a result, short-lived. I broke the one of the back of my K27 very quickly whilst fitting a rear coupler. The pictures show what I did to the K27 bit that same will work on the K28 and I will be applying this fix as I do the sound install.

First thing I did was file off the broken stub of the metal air hose and then drilled a hole through the bracket.

to replace the metal hose I decided to use a San Juan flexible rubber hose. These come in a pack of 8 and are injection moulded in rubber. They come with two stubs to go into holes in the body work. Rather than drill a second hole I trimmed the top stub off. The lower stub was then just fed in to the hole and the joint flooded with Dr Mike2s cyanoacrylate glue.

The back of the tender now has a reasonable representation of an air hose which is very flexible and should just move out of the way of any obstacle.

The rubber mouldings have a bit of flash on them that is a bit of a trial to clean off but I think I will be fitting all of my engines with this arrangement in the future.     

Well that'll teach me to get ahead if myself with these notes. I've just got to the back of the tender on the K28 I'm installing the Tsunami in and it already has a rubber hose. Brilliant I love having less work to do.     

 
  Snow Plows
 

The model of 472 shown further down this page came with it plow attached. Models that didn't have the plow attached should have had one included as an optional extra in the box. Of the selection of boxes I have opened here about 25% had the plow and the others didn't. The factory in Korea forgot to include them and are shipping them to PSC in the last week of June.

My customers have been given the option to claim one if they want one and I will get them from PSC and distribute them once they make it to the UK. If anyone else [other than my customers want their plow I suggest they contact PSC or their dealer directly
 
  Working Front Coupler
  Coming Soon
 
  Damaged Cab
 

Those of you that bought your K28 from me and received our introductory notes will know that whilst most of the engines came air freight on a pallet I had one that came on its own and arrived looking like the post office had decide to see how bouncy it was.

The major damage was that it had received a major blow to the rear of the cab roof which had bent the front of the can forward at the two outer corners as shown in the photographs. Fortunately this was one of the spare engines and not one of the ones already spoken for. It's going to get repaired as part of a customising job so I thought it would be worth documenting it here as it will show how I fixed it and some of the ideas I had for customising.

First job was getting the cab off. This is a bit sneaky. First thing I did was remove the chassis as per the instructions above.

Next there are two screws under the cab that go up through tabs on the cab back into the stems of the seats. Unscrew these if you can. One on this engine was seized and had to be drilled out. Now the seats should drop out and the cab back and roof come off as one. The front of the cab roof has some hooks that fasten under similar hooks on the cab front and it is these that have pushed the cab front forward.

With the cab back and roof off I found it was possible to bend the cab front roughly straight and then clamp it to glue it in place. The cab sides are part of the main engine die casting whilst the front and back are additional pieces of brass.

The picture shows one side glued, I used Dr Mike2s, whilst the other side is being glued showing how it was clamped whilst the glue sets. The wooden block ensures the clamp is pressing on the front of the cab and not on the front of the side die casting.

The next stage in my plan was to araldite small pieces of brass angle in the top corners to reinforce the join.

I said was because the cunning plan now is fit opening cab front doors because many of the photos of the engines show them running with the doors open to get some ventilation into the cab. I suspect it may be a lot of extra work but it will customise the appearance of the engine.

 

This little project with the doors may take awhile and I wish I had thought of it before I did the gluing.

As the cab front is now glued in I might just refit the roof to make sure the planned fix will work and it will also let me complete writing up this section of these notes.
 
 
 
  Reach Rod
 

It seems to me that many of the K28's have shipped without reach rods.

In this view of 473 you can see the reach rod as the horizontal bar that runs under and parallel to the air reservoir. At the right hand end its connected to a crank arm on the valve gear and at the left hand end it goes into the cab and connects to the reversing lever in the cab.

In this picture of the model of 474 the yellow line shows where it should be and that it is noticeable by its absence.

 

 

 

 

 

If it were there, as on the model discussed below and as on the K27 you would have to unclip the right hand end before you can remove the body.

 

 

 

 

 

 

 

 

Now lets have a look at 478. 478 has a power reverse fitted. The left hand arrow points to an air motor for the reversing gear

The right hand arrow points at the reach rod from the air motor to the valve gear.

 

 

 

 

 

 

This picture of the model of 472 shows the model of the air motor and the reach rod.

This had to be unclipped at the fork end on the right hand end.

So far of all the engines I have unpacked here [bare in mind I shipped most of the engines to customers unopened] this model of 472 is the only one that has had the air motor and a reach rod modelled.

I don't know if it is a coincidence but it also came with its plow mounted

 

Here's another twist to the saga. Having asked on the internet discussion groups for info on the power reverse, which engines had it and when I received this response which suggests that whilst this model of 472 has the power reverse faithfully reproduced 472 would never have had it

"From all that I have found over the years, the only K-28 Locomotives I have found to have the power reverse were the 473 and the 478. As you may know seven (7) of the K-28 went to Alaska in 1942. From what you and I have both been able to find, none of these locomotives were ever outfitted with a power reverse, that would include the 472. 

Just for the record those locomotives were 470, 471, 472, 474, 475,  477 & 479.

After the San Juan Passenger service was discontinued in 1951, the remaining K-28's were more or less assigned to Durango. The 476 was the favourite of the Durango crews and in particular the most senior of the Engineers, so it was the primary Road Power for the Silverton  Trains in the 1950's. Since, during this time period, the Silverton Train was (I think) only twice a week, 473 and 478 were assigned as  Yard Helpers in Durango. The D&RGW were using the remaining K-27 as Switchers until they wore out and then the K-28 took over. To assist  the Durango Yard Crews the 473 and 478 were outfitted with the Power Reverse units. When it was necessary for the 473 and 478 to pinch hit for the 476,  it became clear that the crews didn't like the power reverse units out on the mainline as they tended not to stay where the crews put  them and required lots of attention. Not exactly sure when the units where taken off, the Mid-1960's I kind of remember."
 
 
  Prototype Photo's
 

In preparing these notes and similar notes on the K27's {not published yet} I was looking for photo's on the internet. There are doubtless many sources on the web but I'll list the ones I've found here. Hopefully, others might contribute.

http://www.drgw.org/

THis is a fantastic site for history of  all the D&RGW engines.

For pictures click on "online data" - "rosters" and then the loco number the

http://www.durangotrain.com/about/roster.htm

This is the site of the Durango & Silverton Railroad where the last of the K28's now live