Repowering an HO Bachmann Metroliner

thats one way to do it! looks good!

green_elite_cab wrote:thats one way to do it! looks good!

Hi, good morning.

Thank you very much by your comment.
The model didn't became so perfect like its similars in the US, but I tried to use what I have at this moment.
Anyway, I'm having a small problem with the transmission axles which have low mass and they're in resssonance with
higher speeds. I'm making two brass cilinders (50mm lenght by 5mm in diameter) to increase the proper mass of these
axles, reducing the risk of residual ressonances.
Below I'm sending two small videos taken in my railroad model club in Sao Paulo with the Metroliner fleet running.
This is the maximum speed without the problem described before. I think that I'll get a little more speed, which will be
enough for me.

Best regards

Carlos

What excellent mechanical work you have done there! I admire your drive to make the unit run as quiet as possible. Keep up the good work!

I'm not sure how to fix your problem, though prototype Metroliners usually ran in 4 or 6 car trains, so if you took some cars off that one train, it would be lighter and then probably go faster without resonating.

Hi, green_elite_cab, good morning!

In the last night I tested my system and my theory seems to be correct.
Increasing the rotation slowly, there is a point where the power shafts enter in ressonance state.
The origin is clear: there isn't a perfect alignment between both ends and the middle section of the power axles' assembly.
I need a device for my Dremel tool and manually it's very difficult to work these little components.
I modified these sections, changing the metal tubes by plastic ones, with larger diameter (empty pen refill) and the
situation became better, but it's still not perfect.
Anyway, I will get two machined stainless steel round bars in my job (1/4" diameter x 50mm long - with one blind hole in
both ends - 2.5mm diameter by 15mm deep) and probably the solution will be reached, I think so.
I'll inform the results very soon.
Best regards
Carlos

I wonder if its a balancing issue? I know on a driveshaft for a car they actually put them on a machine and balance them. They then add weights to them where needed, just like balancing wheels. An unbalanced driveshaft in a truck or RWD car would give you alot of unwanted noise and vibrations at certain speeds.

Upon reviewing your earlier photographs, i think the problem is that your "inner" drive shaft bearing looks very loose. I noticed that you almost totally removed the the heavy metal plate that held the motors and things in, leaving only the ends. I think you need to have both ends secured to avoid the shaking, and with it the resonance.

Perhaps you can fabricate a new retainer for the inner bearing set. You could also use neoprene tubing between shafts, which will hold it pretty well without the sound issues.

ApproachMedium wrote:I wonder if its a balancing issue? I know on a driveshaft for a car they actually put them on a machine and balance them. They then add weights to them where needed, just like balancing wheels. An unbalanced driveshaft in a truck or RWD car would give you alot of unwanted noise and vibrations at certain speeds.

Hi ApproachMedium, good night.

In fact, both power shafts aren't in a straight line assembly. The main reason is the inside diameter clearance of the plastic tubes where the shafts are fitted in. It's very difficult to find a "glove" to match both inside and outside diameters of the tube
and power shaft.
I think that the solution is the new stainless steel round bars, with high tolerances in the assembly holes in their both ends.
The adjustment will be very fine, without clearance and in straight axis.
I also bought two additional pairs of another kind of power shafts from Frateschi, with different coupling edges, similar to the Athearn models. My mission in this moment is to find the ideal balancing point, improving the power transmission and allowing a higher speed for my engine.
Many thanks by your return!
Best regards
Carlos

green_elite_cab wrote:Upon reviewing your earlier photographs, i think the problem is that your "inner" drive shaft bearing looks very loose. I noticed that you almost totally removed the the heavy metal plate that held the motors and things in, leaving only the ends. I think you need to have both ends secured to avoid the shaking, and with it the resonance.

Perhaps you can fabricate a new retainer for the inner bearing set. You could also use neoprene tubing between shafts, which will hold it pretty well without the sound issues.

Hi, Green Elite Cab, good night.

My drive shaft bearings are the regular model made by Frateschi. I was checking the system of my Athearn models (all of them are from the 80's, US made) and, in fact, those transmissions are much better. As I said in my first message, It isn't easy to find some foreign parts in my hobby shop, in spite of the fact it's an Athearn, Kato, MTH, Atlas and many other brands' dealer. The final price, here, of a Kato or Athearn trucks including all the transmission system aren't suitable for this case.
Anyway, Green Elite Cab, I believe that the solution is very close, and the stainless steel round bars have to be the answer.
I didn't preserve any part of the original Bachmann metal chassis, only the detailed original plastic bottom. All the frame
came from a Frateschi GE U20C chassis. There is a lead weight in the middle center of the frame and two stainless steel
flat bars increasing the engine's weight.
The motor is a genuine Atlas dual brass flywheel model - its price was US$30.00
Remembering that the trucks originally were designed for freight locomotives, then, I probably will never simulate a 125mph
speed.
I'm forwarding one additional video of the engine, running yesterday in the club. In this speed there is a very low transmission noise. It's equipped with plastic tubes "gloves" in the transmission.
Best regards
Carlos

Hi, ApproachMedium and Green_Elite_ Cab - good morning.

One of the best features of model railroad is the continuous knowledge you get in the maintenance of the models.
Yesterday I received the two 1/4" dia. stainless steel round bars from a friend which works in the production line.
The assembly became perfect, but I had a suprise: the bending in the middle of the power shafts was fixed, obviously,
but the ends didn't support the bars weight. The solution would be aluminum bars but we don't have this size of material at
this moment. Then, I saw another way to solve this equation: I can use the power shafts in their original dimensions
(as they are used in the Frateschi locomotives) extending the two flywheels in both directions about 27mm (almost one inch). I have this size of aluminum round bars in the company, and I will try this solution. The result will be more mass in
the flywheels, which is better to increase and decrease the engine speed. The motor axle diameter seems to be enough
to support these masses without deflexion, but the test will show me. Let's see what will occurs....

Hi, good morning.

Extending the flywheels was a very different attempt, but also it didn't work. The exact alignment of two rotating parts is critical and very hard to do without an industrial-sized equipment. It was an another good learning process in the search for the ideal power transmission for my Metroliner engine.
Another constructive option thought, to which I am working on now, is the use of two motors, each with its drive shaft, and connected to another one to the rotation synchronization . It is,in fact, the same assembly applied on the dual motors version of the Athearn's DD40. The system is already mounted, but with an Atlas motor and a Bachmann one(the original which came with the Metroliner), but I will leave the two engines alike. I tested the solution yesterday and the result was good: the ressonance disappeared completely, and the motors reach their maximum speed without structural instability by vibration, but the coupling shaft is very rigid. I'll will try to find a better material. Very soon I'll will write here about the results.
Best regards and have an excellent day.
Carlos

Some pictures of the dual motor assembly. The feature to be improved is the power axle between the motors.
The ressonance/vibration is gone.

That looks awesome! Gonna have to find a way to replicate that!

green_elite_cab wrote:That looks awesome! Gonna have to find a way to replicate that!

Dear Green Elite

I am fully confident that you will not only replicate this setup but you will also optimize it with the high tec materials
that there exist in the United States. Next Saturday I will seek an appropriate power axle to join both motors, and I will go to my club again to test the Metroliner. I will do this until I reach the goal of equipping the train with a good speed, good traction and low noise. The cost of the materials I used here in Brazil was extremely low (about $30, except the motor), but I believe you will be able to do a good job with less than $ 70 or $80, in the US.
Wait for news in brief

Hello, good evening

Except for minor modifications to fit the mechanics of my Metroliner, I think I reached my goal, having at hand the materials available for my work. Today I took my train back to the club and tested it with the new drive shaft between the two motors. The result was even better, and going forward, to obtain performance similar to a high speed train, I'll have to look
per high rotation motors, or else look for compatible B-B trucks (on EBay) having a smaller gear reduction ratios, which will increase the final train's speed. Only practical tests will determine the ideal (or final) solution.
I don't know how to evaluate effectively the speed of the model, perhaps someone can explain or help me about this.
I'm attaching pictures of the final assembly (until this moment) and two videos with the Metroliner running with 75% and 100%
of the controller speed range. The only next change will be leaving the two engines exactly alike, nothing more.
For those of you who live in the United States, I can not even imagine the amount of possible options to be employed , not necessarily with spud trucks or something equivalent . I believe that with a cost-effective classical transmission, similar to locomotives from Athearn or Atlas everyone can solve their problems with the Metroliners easily.

Below, the drive shaft between the Bachmann and Atlas motors:






Here the video with Metroliner running at 75% of controller speed range:



Here the video with Metroliner running at 100% of controller speed range:



Every opinion will be wellcome, mainly about US options for higher speed trucks (not spud trucks)

My best regards

Carlos