MaxiTram

[velotrain]

I really enjoy watching an articulated tram snaking around tight curves.

The Tomytec Tetsudou Collection Santrams, powered by the TM-LRT02 chassis, are my favorite.  When I first got into Japanese trams last summer, I had three of them, and would run them together with the slowest in front and the fastest in the rear, so I effectively had a nine segment tram.  I've been working - off and on - to build a single unit, seven segment tram. 

 

 

 

 

Today, I decided to take a break from that and make the much easier five segment version.  As you can see, it's just a little shorter than two stock Santrams.  I will be epoxying the two hacked chassis together, but for now they're just joined by the curved sections at the ends of the bashed center body segment.  I'll be replacing the panos, and doing some light weathering. 

 

I decided that the Hiroshima Piccola cars would look great in this format, and just ordered a couple of shells.  One nice thing is that you can easily swap superstructures on the chassis in under a minute.

 

 

 

 

Due to the length of the center segment, it will not run on R103 curves.  However, it seems to handle whatever R140 track I throw at it, including reverse curves.  Inspired by this, I'll pick up work on the seven segment tram - which should handle R103.  Since I know some of you will want proof that it's not a static model, here's a short video.

 

https://youtu.be/B22evuRA7UQ

[cteno4]

nice job, runs well on your torture test!

 

been on my list to do some hacking and whacking like this. 

 

jeff

[velotrain]

Your experience with the "green monster" is part of what made me want to try it ;-)

 

This is fairly simple, as it only involves bashing two of the shell ends, and two of the chassis ends - but do check what direction they run in first !

It took maybe 3-4 hours, and probably only two if I did it again.

I removed the door from both pieces of the shell, partly for length reasons, and also since I thought it looked wrong at the ends of the new middle section.

 

With the seven segment version, I'll need to bash two new hinges, and do a lot more body work.

[katoftw]

Interesting.  I Think Greenmax did the Hiroden Big Green Mover.  It was a hit and miss runner from all reports.  Yours looks to be a lot better.

[kvp]

Interesting. I didn't think the Tomix mech had this much flexibility in the end sections, to allow movement of the two center bogies. Or the housing has been modified to allow this movement. The big mover is a fixed chassis design with one bogie per section, this is a fixed-suspended-conventional twin bogie-suspended-fixed arrangement. There are some trams in real life that follow this design.

[velotrain]

No modifications other than shortening one end of each chassis unit, and bashing the center body section.

 

The way I see it, there isn't really any movement of the center section - everything else pivots around it.

 

Think of it as a 4-8-4 steam engine ;-)

[velotrain]

Or should that be 4-0-8-0-4 ?

[kvp]

Yes, aka. B-D-B, but if it's this rigid, then i'm really surprised that it can navigate R140 curves and turnouts. This means several larger steam and electrics might also make it.

[velotrain]

I was only describing the wheel arrangement, and emphasizing that the ends flex more than the center - which really can't with two fixed bogies.  As with the leading and trailing trucks on a steam engine, the job of the ends is to guide the main wheels, and in this case the segmented body. 

 

I only shortened the two chassis units on one end, so each still has two flex points.  As originally configured, these units handle R103 with ease.

 

"larger steam and electrics" generally don't have articulated chassis or superstructures.

[velotrain]

Here is the tram with "the hood off"

 

 

 

 

This shows it on a curve.  I have the center body section on to keep the two chassis end sections straight, as I have not epoxied the chassis together yet.

 

 

 

 

Here I have removed the body section, allowing the chassis to have full flex.  While leaving the center on the rails, I have bent the ends to illustrate the full range of flexibility.

 

 

[kvp]

Actually some older japanese ones do have articulation, even if only bogie mounted platforms before the main body. The interesting part is the large rigid wheelbase of the middle section. It corresonds to a 4 coupled axle steam or electric lok. I'll have to check my hiroshima tram for possible play on the end bogies. That would explain a few things or make more questions.

[velotrain]

This discussion has given me a new idea.  Even though the middle body shell restricts pivot of the middle two bogies, I now wonder to what extent minor flex might be taking place in there while running around curves.  It's possible that epoxying them might produce a problem that I haven't encountered.

 

I'm thinking of slightly rounding the two chassis ends where they meet.  However, I don't want to do that on the sides where they join the body, as I'm afraid this might produce noticeable "bouncing" of the body piece when the chassis parts flex.