Search the Community
Showing results for tags 'traintech'.
Found 1 result
-
Dear all, as discussed in the TrainTech forum, I am posting here in the Community forum some modding on a 10-wide BR 89 fully LEGO compatible display model from BlueBrixx, I got as birthday present this year. Why in the Community forum? Because this is - well - a BlueBrixx (BB) set MOD - mostly using LEGO stuff though. This is how she currently looks like (see below for changes to the original BB model) featuring a PoweredUp (PUp) City hub, PUp L motor, PUp color sensor, and custom rods: The TrainTech forum post referenced above shows in addition a turn table I made explicitly for the BR 89 – as I don’t have any more space in my attic to 1) accommodate a full circle of track and 2) no more floor space at all. Which means she has to run on slightly curvy track mounted to the sloped walls in my room, and since I don’t want her get too bored when just steaming back and forth, I thought she might enjoy being turned around at one end of the track section from time to time … Why the BR 89? Because I got her 50 years ago as H0 model from Märklin (in German) as Christmas present from my parents – but then really never got into model railroading – LEGO just was so much more attractive to me back then. Nevertheless, this engine is still available today from Märklin, and the 10-wide BB model looked really nice to me on their website. Some remarks BB BR 89 original set €70 – which a very good deal, bricks and plates with good quality having mostly superior clutch power as compared to LEGO pieces. Colors: I am a bit color-blind, but an expert on shades of gray, and there is room for improvement (some black pieces). However, I like the less perfect, less glossy appearance of a steam engine – have never seen a real one, even when perfectly restored, in super-glossy colors. Changes/additions Rebuilt the lower frame/driving gear/running gear. Main changes: Front axle driven by a PUp L motor (original: center axle/BB PF M motor). This also allows removing the clearly visible “Technic gear 20 Tooth” as seen in this step of the original BB instruction: Furthermore, narrowed the frame at the center axle/wheels from 4- to 3-wide, allowing the flanged center wheels to move inward when negotiating corresponding curves. As the BR 89 is running in eye height in my room, I simply do not like the blind wheels. These are perfect and unavoidable in other builds, however in this case I reverted to the split axle design originally shown by @Ben Beneke on his BR 23 and used all six wheels with flanges. I have motorized Ben’s BR 23 over 10 years ago using the same approach as shown here:With regard to the 89 it is even tougher for her to manage R40 curves, see MLCad picture below, as the front and rear axles are 13 studs apart and the big train wheels don’t help at all. On the split axle there is a piece of medium soft foam inserted between the “Technic axles 2” pressing the wheels very gently onto the connecting rods. When going through a curve, the inner wheel is moving correspondingly and moved back on straight track: Lowered the position of the motor within the frame and moved it forward. This is required when the cabin space shall remain (almost) as “spacious” as in the original, as the PUp L motor is two studs longer than a PF M motor. Added/moved some plates here and there to make the frame a little sturdier, as it became rather “brittle” with the PUp L motor installed. Rebuilt the lower section (frame) of the smoke box to attach a PUp color sensor facing down as well as for the wires (motor and sensor) and accommodate a PUp City hub, which is 3 plates higher than a BB RF battery box. The upper body of the engine seen from below in the picture below does not fit this way onto the frame - this was work in progress. I disassembled the upper body layer by layer and rearranged the layout on the fly when building up the engine on the new frame: Rebuilt, raised (1/2 stud), and moved (1 stud) the cylinders so that the valve gear still runs free, the piston rods are almost on the same height as the wheel axles, and the main rod does not become too long: Moved the connection point of the main rod to the rear wheel (as in the real engine) using custom connection and coupling rod(s) and added some "valve gear": And placed the PUp City hub partly on top of the motor with a one-plate-spacing for the wires: An ESP32 Dev kit (nothing else required, about 10€) programmed within the current Arduino IDE (C++) using the current Legoino library from Cornelius Munz is controlling the setup (turn table and engine operation). Manual control can be done with the PUp remote (left dial keys: turn table motor fwd, rev, stop; right dial keys: BR 89 motor fwd, rev, stop; center key: emergency, all hubs turned off immediately), however this is intended for debugging only, as the setup runs autonomously. The turn table features a PUp L motor as well, so on both table and engine, repeatedly pressing the fwd key increases speed (not power) by 5% using a smooth acceleration profile; same for rev. Stop is a brutal stop though! Some remarks on the original BB BR 89 set: As said, the original BB version is a display model. It features 6 flanged driver wheels; in addition, they give you two blind drivers as well – which tells you that this model is already sturdy enough to go through curves. The original idea is to put the engine onto a (very nicely done!) stand, which elevates it slightly above track level, and then use a BB PF compatible M-motor along with the BB RF battery box and RF controller to "just" turn the wheels. A PF M motor is not powerful enough to run her on track. YouTube's user Bricked4You has published some very nice videos on retrofitting the original display model into a nicely performing LEGO track compatible engine (in German), which is also nicely coping with R40 curves, using a BB PF-L compatible motor. Instead of using BB’s PF compatible stuff (L-motor, RF battery box, RF controller) I wanted to operate my 89 with TLG’s PoweredUp gear – why? Because using a tacho motor (e.g. PUp L motor - BL price for a new motor is about 1/3 of what LEGO asks for on their shop website) along with the “SetSpeed” command (rather than “SetPower”), she moves slowly but steadily, curved track or not, i.e., is far less affected by changing friction forces. The regulated rpm setting is ensured by the motor’s built-in rotation sensor and the PoweredUp hub hard/firmware, which reads and translates the rotation sensor data into appropriate power settings to maintain the "desired" speed. I really like to watch the valve gear when a steamer moves slowly … And I wanted the entire setup (BR 89, turn table) to run autonomously without any user interference (other than moving the BR 89 into startup position). One issue in this scenario is “safety”. When the 89 dives from the approximately 1.5 m height and crashes into the 9/12 V train layout below, serious damage is to be expected – and I don’t want that to happen (I also don’t like crash-videos ...). The TrainTech link given at the top of this post shows the (elevated) track the BR 89 has to negotiate along the wall. (Note that the following two files are deep linked on BrickShelf - thus you are taken directly to the file content. When moderated, I will change this to point to the files) LDraw model including the PUp stuff is available here (note that there are two versions of the drive mechanism – the “new” one is described here); current Arduino sketch as well – rename .txt file to .ino to load it into the Arduino IDE. Video will hopefully follow in a couple of days, I sure hope – I am terrible at doing videos . Best regards, Thorsten P.S.: YES, there is also real cheating going on here : I filed off the "flange"(?) at the long side of the "Technic Pin 3/4" (LDraw #32002), which is driving the center wheel and thus needs to slide in and out in curves as well, as the wheel is moving but not the side rod. On the short pin side, it is legally attached to the center hole of the custom side rod. The would-be Walschaerts valve gear is missing (among many other things) the union link - and the combination link is made from a broken "Technic flex system cable". The intact cable terminal is legally fixed to the upper "Technic flex system pin hole connector" (LDraw #2900), the broken cable terminal is (illegally) just sliding in and out of the lower connector. I like illegal stuff
