Bachmann Thomas Loco #1

[Madman]

My, and my grandchildrens, Bachmann Thomas loco arrived yesterday. Appearance is very nice. I spent some time last night converting it to run on battery power. Very simple, just cut the wires that go to the track pick ups and rerouted them to a scractbulit lighting socket on the rear of the loco.
Today was trial running time. I am seeing some issues when the loco goes into an LGB #3 turnout from the single end. I think it is track issues, i.e. not being quite level enough. I also think that the loco could use some addition weight, which may help it in tracking. A leading truck or bogie would probably be of some assistance also. But that's too much of a project at this point. The drive wheels have virtually no movement up and down, as do LGB drive wheels. I need to look at that issue. In my wildest thoughts I figured elongateing the drive axel openings in the frame. But that may be alittle too risky.

Any thoughts?

 

[modeler]

Yes, extra weight is definitely the order of the day. If there are coaches involved, you may want to consider adding some weight also. My Thomas engine was so light that a healthy sneeze would send it off of the rails. It does keep one vigilant until the tracking improves.

 

[Madman]

I was tinkering with Thomas this evening by adding some lead weight. Also I opened up the motor block from the bottom. The center driver is the powered driver. Somewhat odd, but hey it works. The first and third set of drivers are powered merely by the side rods. The axels ride in brass bushings which are grooved to fit the sides of the motor block. I was able to file some of the plastic from the axel bushing slots in the motor block. I also filed some of the plastic from the half moon bushing retainers on the motor block cover. This allows the brass bushings to have some up and down play. Tomorrow I'll give it some more trials on the track.

 

[spoz]

Don,

I regularly drive my essentially unmodified Thomas (battery and RC so some added weight but not otherwise) through R1 and R3 turnouts; I occassionally have a problem on the R1s, especially when approaching on the diverging route but have never had a problem on the R3s. Problem on the R1s is I think related to the fixed wheel base although I don't have problems with either an Annie or an Indy and the Annie certainly has a longer wheel base; but of course both have has the front truck to guide them. Mind you, my Thomas only has 14.2 volts so it can't career into the turnouts at high speed; that's a defence against what the grandsons would do if they have the chance!

For some reason, it's not the R1 on the upward slope that is where the problem occurs but another which is on the level (and it IS level in both along and across the track); and it only occurs when pulling a train and going forwards so perhaps the front wheels lift slightly, or at least the weight comes off them?? (Thinking on my feet so prepared to be shot down).

Steve

 

[trammayo]

I was tinkering with Thomas this evening by adding some lead weight. Also I opened up the motor block from the bottom. The center driver is the powered driver. Somewhat odd, but hey it works. The first and third set of drivers are powered merely by the side rods. The axels ride in brass bushings which are grooved to fit the sides of the motor block. I was able to file some of the plastic from the axel bushing slots in the motor block. I also filed some of the plastic from the half moon bushing retainers on the motor block cover. This allows the brass bushings to have some up and down play. Tomorrow I'll give it some more trials on the track.

Hi Dan. I find that even 12 volts is too fast (compared to other Bachmann locos!). I do wonder about giving vertical play to the axle/s. Only gravity keeps the wheelset in contact with the track unless there is a method of applying downward pressure like springing.

I run the Thomas range (in the main) on my trailer layout which is all R1 curves and switches - both facing and trailing - and with reverse curves too. There are no problems with the locos derailing although, to be fair, the track is all screwed down and is level (or on the same plane at least). I have a mixture of LGB and Aristo switches.

 

[ntpntpntp]

... The center driver is the powered driver. Somewhat odd, but hey it works. The first and third set of drivers are powered merely by the side rods.

To me, it's odd that you would find that arrangement odd, Dan In the UK that was standard fare for things like Triang Hornby of the 60s/70s/80s. Personally I find that arrangement better for lower quality mechanisms with wider tolerances and which rely on rods to transfer the power, as you get equal "sloppiness" either side of the drive and a smoother run in both directions.

I've come across mechs with the motor drving one end and no internal gears to couple the other wheels, where there's been so much play in the rods that the "far end" drivers have had an awful waddle in one direction or the other and no amount of adjustment to the quartering would cure it. Funnily enough it was older Bachmann OO/HO mechs that come to mind as a prime example!

 

[Madman]

I was tinkering with Thomas this evening by adding some lead weight. Also I opened up the motor block from the bottom. The center driver is the powered driver. Somewhat odd, but hey it works. The first and third set of drivers are powered merely by the side rods. The axels ride in brass bushings which are grooved to fit the sides of the motor block. I was able to file some of the plastic from the axel bushing slots in the motor block. I also filed some of the plastic from the half moon bushing retainers on the motor block cover. This allows the brass bushings to have some up and down play. Tomorrow I'll give it some more trials on the track.

Hi Dan. I find that even 12 volts is too fast (compared to other Bachmann locos!). I do wonder about giving vertical play to the axle/s. Only gravity keeps the wheelset in contact with the track unless there is a method of applying downward pressure like springing.

I run the Thomas range (in the main) on my trailer layout which is all R1 curves and switches - both facing and trailing - and with reverse curves too. There are no problems with the locos derailing although, to be fair, the track is all screwed down and is level (or on the same plane at least). I have a mixture of LGB and Aristo switches.

When I had the motor block open, last night, I could see that installing a spring to push down on the first and third set of drivers would be a simple task.

 

[Madman]

I was tinkering with Thomas this evening by adding some lead weight. Also I opened up the motor block from the bottom. The center driver is the powered driver. Somewhat odd, but hey it works. The first and third set of drivers are powered merely by the side rods. The axels ride in brass bushings which are grooved to fit the sides of the motor block. I was able to file some of the plastic from the axel bushing slots in the motor block. I also filed some of the plastic from the half moon bushing retainers on the motor block cover. This allows the brass bushings to have some up and down play. Tomorrow I'll give it some more trials on the track.

Hi Dan. I find that even 12 volts is too fast (compared to other Bachmann locos!). I do wonder about giving vertical play to the axle/s. Only gravity keeps the wheelset in contact with the track unless there is a method of applying downward pressure like springing.

I run the Thomas range (in the main) on my trailer layout which is all R1 curves and switches - both facing and trailing - and with reverse curves too. There are no problems with the locos derailing although, to be fair, the track is all screwed down and is level (or on the same plane at least). I have a mixture of LGB and Aristo switches.

Yes, and to be fair to Thomas, I have discovered that two of my R3 turnouts is not quite as level or at least on one flat plain as they should be.

 

[Madman]

Well I had some time to test the loco again. With the small amount of weight added, not too much better. Then it was back to the work shop. I opened the gearbox again. This time I took more material off of the axel cutouts of the gearbox cover. You can see how much material I filed away by comparing the two photos. The center driver was left alone. Then I installed springs under, or above depending on the position of the loco on the workbench, the front and rear axels. I found these springs in my plumbing parts drawer. They are parts for repairing Peerless faucets. I libed them and checked to make sure all of the axel bearing parts had not lost any grease do to my handling. Finally, after replacing the gearbox cover, I removed the superstructure and added lead weight. The loco now weighs in at 4 pounds 12.6 ounzes. I did not weigh it before I added the weight so I cannot compare the figures. I do know, however, that picking it up now feels quit different. As daylight was diminishing I had only a few minutes to retest the loco. Vast improvement. I'll post more after some extensive trials.

 

[Madman]

Well, the picture inserter thing-a-ma-jig still does not like me. So some photos got missed, while others had more than one vote. Oh well.
The one photo I wanted to show was the one showing what the axel cutout looked like after I filed it. I'll try it here.

 

[CoggesRailway]

Yep dan more weight needed. Thomas is however my least tolerant loco for unlevel track as it is relatively rigid. We put through 36v through ours when we were messing around- it becomes TGV Thomas
With more weight it runs very well, and it runs about the right speed at 7.2v.