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  • Topic: Bachmann Spectrum 4-4-0/2-6-0 Tender truck fix

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    • July 4, 2020 1:42 PM EDT
      • Fort Myers Beach & Annapolis, Florida & Maryland
         
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      Bachmann Spectrum 4-4-0/2-6-0 Tender truck fix

      This is a Tale of Two 4-4-0s, the 1:20.3 Spectrum locos from Bachmann. My pal Jerry and I picked up a couple of derelict ones for a song, along with a 2-6-0, and we've been fixing and updating them. Both the 4-4-0s were working on track power, and suddenly Jerry's loco's tender started derailing in 2 or 3 spots around his railroad.

      Yesterday I took my tender over to his track and it ran perfectly. His was still derailing, and I could feel that a front truck wheel was lifting over the railhead in those spots, and at least one was where the track camber changed at the end of a downhill curve.

      So I left my tender and brought his to my workbench to try to make the trucks more flexible. He also seemed to have a bent axle, which I straightened when I got it on my bench.

       

      Sheesh, those trucks are tough to get off. Not only do you have 4 dangling chains that need to be carefully detached, but there is wiring for the wheel pickups and brake gear. [Tip: I pulled the chains out of the holes in the top of the trucks. On reflection, I think you could open the ring on the pin on the truck with needle-nose pliers, and remove the chain without pulling the pin out.]

       

      The wiring is a slight piece of bad design - a nice loop soldered to the wire screwed under the pickup strip, but the loop won't go through the hole in the bolster!  The pickup screw also holds the brake gear on, so it can be popped off once you have the wires unsoldered and loose.

       

       

      The first thing that became apparent is that the truck bears a slight resemblance to the only reference drawing (for the 2-6-0) on Bachmann's website.

       

       

      The first difference is that the little screw under the sideframe holds the spring box in place. (A nice touch - the springs do not fly everywhere.)

       

       

      Now, with the springs gone, we can see the big screw holding the sideframe to the bolster. (Which is not on the drawing.)

       

       

      Pop out the screw and you find a shouldered boss with a couple of ears to stop it rotating.

       

       

      Wrong! We want it to rotate a little - the sideframes need to be able to move up and down about that central pivot. So the flat file is brought to bear.

       

       

      This pic is after reassembly, to show you how the truck is supposed to behave. A change in rail height at one side does not make any wheel leave the track. There is a lot of weight in the tender, so the big screw doesn't need to be very loose - just enough to let the sideframe move.

       

       

       

      Once back on the tender body, I shot a quick video to demonstrate the issues.

       

       

      The rocking shown in the video is due to the boss of the pivot sticking up into the bolster too far - the washer and screw leave a gap which lets the truck rock from side to side.  One one truck I inserted a shortened spring from my scrap box (pic,) and on the other truck I found a small silicon O-ring that was just the right size. Neither truck mounting screw was tightened too far - both trucks need to be able to rotate!

       

       

       

      So, as the video shows, I had one floppy truck and one solid one. Having discovered how it was all put together, it occurred to me that I could remove the sideframe without taking it all apart.

      Out pops the little spring box:

       

      Revealing the bog screw, which is taken out.

       

      With the sideframe loose, even if still attached by the chains, it is possible to file down the ears on the boss a little.

       

       

      And then it is easy to re-install it, with the screw tightened and then backed out 1/4 turn or so so that the sideframe can just move up and down. Much easier!

       

       

      Finally, as my tender is over at Jerry's, I have a substitute, so here's what the locos look like with different tenders.  The 2-6-0 on top has an Aristocraft 2-8-0 tender body on the usual frame. (Thanks to Kevin.) Inside is a Revo, sound and battery set-up.  The 4-4-0 has a temporary LGB Mogul tender. Interesting that it is 1:22.5 and is still larger than the other tender.

       

      This post was edited by Pete Thornton at July 6, 2020 6:04 PM EDT
      ____________________________________

       

        Pete

    • July 4, 2020 8:53 PM EDT
      • Curmudgeon at Large, Insurance Warrior
         
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      Pete, I don't own a 4-4-0 but I do own a Mogul that needs some TLC. For now it is a back burner project, but this is a very nice write up on fixing a tracking problem shared by all rigid trucks. I will definitely incorporate this into the fixes on my Mogul.

       

      Might I suggest you ask BD to locate this in the Articles to make it easier to reference later on?

       

      Bob C.

      ____________________________________

      We don't stop playing with trains because we grow old, we grow old because we stop playing with trains.....

       

    • July 5, 2020 4:33 PM EDT
      • Fort Myers Beach & Annapolis, Florida & Maryland
         
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      I almost forgot this picture. When using the close-coupled hole in the drawbar (loco-tender coupler) make sure it is above the brake crosspiece. We found once it was below and trying to lift the front of the tender off the track.

       

       

      Today I took it back to Jerry and it ran flawlessly - no more derailments.  I am a big fan of equalized suspension, where the assumption is that no railroad is dead flat, and therefore you need to allow the wheels to move up and down.

      In theory, you can solve the problem on these rigid trucks by allowing just one side to move. As the bolster pivot is rounded, the whole truck can rock, so just doing one side will give the wheels the flexibility they need.

      If you really want some light reading on suspension, take a look at this.

      http://www.clag.org.uk/41-0rev.html

      This post was edited by Pete Thornton at July 5, 2020 6:21 PM EDT
      ____________________________________

       

        Pete

    • July 5, 2020 5:28 PM EDT
      • Maryland
         
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      Nice work, Pete, thanks for the help

       

      Jerry

    • July 6, 2020 6:05 PM EDT
      • Maryland, USA
         
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      Nicely documented Pete, thanks.

    • July 7, 2020 11:55 AM EDT
      • Fort Myers Beach & Annapolis, Florida & Maryland
         
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      Now I am asking myself why I haven't done this mod on the tender that goes with my 4-4-0. Perhaps because I really never use it - I have a battery r/c 2-6-0 with EBT on the tender, and Jerry has the 4-4-0. Time to sell!

      ____________________________________

       

        Pete

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