Tag Archives: Train

Supercapacitor Power Packs

As an electrical engineer, I have always found lithium batteries to be…. amusing. They’re extremely volatile; if overcharged, they explode. If over-discharged, they explode. If charged too quickly, they explode. If discharged too quickly, they explode. If punctured, they explode. If they get too hot, they explode. If they get too cold, they simply don’t work. Think back to the recent debacle of the Samsung Galaxy Note 7 battery woes. But yet, these are the best batteries that are currently mass produced. Almost everyone carries one in their pocket and frequently holds it close to their face. For applications where the energy density (energy stored per volume) or the total energy stored (in Watt-hours) isn’t important, there is an alternative storage media that might be of interest to my fellow model train fans. Enter supercapacitors.

Not quite the same thing.

What follows isn’t for the electronically faint of heart. Accidentally short circuiting an alkaline battery or similar for a few seconds isn’t going to cause much harm. Short circuiting a bank of supercapacitors will melt wires and turn your supercapacitors into charcoal in no time. Be smart.

A supercapacitor is different than a battery in several important but sometimes subtle ways. For a model train, some of these differences are to our advantage, others are not. First off, when a battery is discharged from 100% to 0%, the voltage is fairly consistent. The difference between the full and empty voltages and the rate at which it falls depends on the type of battery. For example, a NiMh battery is about 1.45V full, and 1.2V empty. A capacitor is different; when empty, it is 0V. The “full” voltage is whatever you charge it to. Different capacitors have different maximum voltage ratings. When discharged, the voltage falls from the charge voltage to 0V. Most supercapacitors are rated for either 2.5V or 2.7V. Similar to batteries, putting multiple capacitors in series is how you get the desired voltage capacity. For example, a 9V system would need 4 2.5V/2.7V supercapacitors in series. When the system is charged up to 9V, the voltage will be split evenly with 2.25V each on the 4 capacitors.

The second major difference between the two technologies is the speed at which they can be charged. NiMh and LiPo batteries are usually limited to some fraction of their amp-hour capacity for their charge rate. Meaning, a 2000mAh NiMh battery can be safely charged at 1-2A. Of course, this varies based on manufacturer specs, and charging them faster will degrade their capacity faster, but that is neither here nor there. A supercapacitor has a much higher safe charge/discharge rate. The small ones I like to use in my locomotives are safe up to 3.3A! Much higher rated ones exist too, I built an experimental system that used 100F supercaps rated up to 35A. Additionally, a rechargeable battery typically is only rated for a few thousand charge cycles. A supercap can be charged several hundred thousand times.

The major downside to supercapacitors is energy density, or how much power you can store per volume. My choice supercaps are 4mWh/cm^3 whereas a 2000mAh NiMh battery is about 350mWh/cm^3. So they’re less dense by about a factor of 100, useless, right? No! If all we need to do is get over an unpowered track section, for example an unpowered ME Models R104 180 degree curve, we only need about 10 seconds of run time. So if we have an equal volume of supercaps to AA batteries, our run length will be 1/100th: an AA battery set lasts several hours, call it 2h on the conservative side. That means an equally sized supercap bank will run for 1.2 minutes, plenty of time for zipping through a short unpowered track section!

Some of the difficulty in implementing a supercap bank is limiting the charge current. From the perspective of your power supply, capacitors are more or less a 0 ohm short circuit which means the theoretical charge current will be infinite. You can limit this with a resistor, but realistically this is unfeasible. A resistor spec’ed correctly would have to be very physically large to allow for high heat dissipation. It’d get hot enough to melt LEGO (ask me how I know)! Additionally, as the capacitors charge, the charge rate slows down exponentially. Luckily, there are other methods available to limit the current. I found a cheap, small product on eBay that fits the bill perfectly: a CC/CV regulator. Not only can this thing limit the voltage to the bank, but it can also limit the current.

With a CC/CV regulator set to never charge past the supercap’s rated voltage and current, the next step is regulating the output of the supercaps. Because we don’t want our train to slow down as the supercap bank discharges, we need a DC/DC regulator. There are some nice cheap ones on eBay for about $1.50 that just so happen to be exactly 3 studs wide.

Above is my Amtrak B32-8WH being retrofitted with 10x 15F 2.7V supercaps. The small circuit board on the left is the CC/CV charger. The wires going down through the center lead to the fuel tank, which is where the DC-DC regulator, bridge rectifier, and bluetooth motor controller all live.
Complete circuit diagram of my supercap system. The bypass diode on the CC/CV charger was later removed.

I’ve also made a system with 10x 100F supercaps. The added capacity doesn’t really add any utility over 10F-20F supercaps, so all of my recent systems are 15F. One of the downsides to charging the supercaps as quickly as possible is the sizing of the power supply required to handle the peak current, especially when you have multiple locomotives on the same circuit. Luckily for me, my work has stacks of 24V 6.5A power supplies lying around. Unfortunately for you, they are not cheap new. A used PC power supply can be rigged up to perform similarly, but as always, the exercise is left to the reader…

Hybrid PF/9V Systems

Following up on my previous article introducing LEGO’s 9V system and their Power Functions (PF) system, I’m going to go a little more in depth about building hybrid systems that utilize both PF battery packs and 9V train track. I’ve developed and iterated through several different systems that combine the best of both and have come up with several easy to implement systems.  Anyone with a few dollars, a volt meter and a soldering iron can hack together one of these hybrids in a matter of hours. Continue reading Hybrid PF/9V Systems

Jersey Girl

Central Railroad of New Jersey 1940’s Commuter Train in LEGO

This is my LEGO model of a 1940’s Central Railroad of New Jersey commuter train. This train is typical of those that made up the CNJ’s short haul commuter service in the first half of the 20th century. You may have already seen the locomotive in my recent article on Vinyl Decals, or on a recent youtube livestream. Now that the locomotive is properly decaled, I finally took some time to photograph the whole train and write this article.

Full CNJ commuter train.

The seeds for building this train were planted several years ago while on a trip to visit Steamtown National Historic Site. While there one of the locomotives that caught my attention was an odd little Canadian National engine,  no. 47. Canadian National no. 47 is what is referred to as a “Suburban” locomotive.  These locomotives were built for short haul service on commuter lines. The Suburban type had its tender, carrying coal and water, integrated with the main frame of the locomotive, rather than having a separate “tender” car semi-permanently coupled to the locomotive. This gave the locomotive excellent dual directional capability, handy for when there were no provisions for turn the engine around at the end of it’s run. It was not uncommon to see these engines running backwards pulling their train on a return trip.

Continue reading Jersey Girl

Decals For LEGO Trains: The Vinyl Option

In my first article in my series on decals for LEGO® trains, I covered some popular model RR manufacturer’s who make decals suitable for use with LEGO trains. This time I want to highlight one of the options for making your own custom decals for LEGO trains, vinyl decals. This is a newer option that I’ve come across but it offers some great possibilities.

The story of how Maci’s Monograms got side tracked into LEGO decals.

This all started some time ago when I came across a post on Facebook about some decals that LOLUG – Lincoln/Omaha LEGO User Group had made using cut vinyl. My friend and fellow train builder Nate Flood is a member of LOLUG and he quickly brought me up to speed on them. As it turns out, Nate’s daughter Maci is the one who produced the decals, and she has started her own business for the purpose.

When you order vinyl decals from Maci’s Monograms, you get the decals, a nice printed instruction sheet showing you how to apply them, and a little thank you note. It makes for a great presentation when you open the package. Locomotive NOT included.

Continue reading Decals For LEGO Trains: The Vinyl Option

The JJ Young, Jr Flickr Collection

2 weeks ago I  wrote about the Barriger Library and the wonderful historical resource it provides for North American railroading. Today I want to point out another great flickr library that myself and several of my fellow LEGO train builders have been drawing inspiration from. The JJ Young, Jr Library.

The John J. (JJ) Young, Jr. Railroad Photo Collection

CNR pacific #5588 is caught racing as speed with the engineer sounding the engines whistle....

Continue reading The JJ Young, Jr Flickr Collection

The Barriger Railroad Library

Today I would like to draw some attention to one of the coolest Flickr accounts I’ve come across in some time. This one does not have any LEGO train content, but at it’s core, it is proving to be an incredible resource for modeling North American railroads.

J&L steel mill is seen from the Pittsburgh & Lake Erie RR mainline looking east toward J&L tunnel, Pittsburgh PA

Continue reading The Barriger Railroad Library

The Union Pacific Type – Building a Steam Locomotive in LEGO

This will be the first in a series of articles about my process of building a LEGO steam locomotive. I intend to cover a variety of topics in this series including research, the use of custom elements, aftermarket electrical devices, and building techniques. While I will focus on a specific locomotive project I am currently working on, this series will not include a full set of step-by-step instructions to that locomotive. My intention is to share some experiences and techniques that I hope people can apply to any steam locomotive project, and perhaps other types of LEGO models as well. At any rate, my designs are usually pretty fragile and don’t really lend themselves to redistribution via instructions. Instead, I will lay out my approach to building a steam locomotive and why I think it is effective. I hope that this will help people who are struggling with what I think is a particularly difficult type of model to build or, at least, be of some interest to the readers of this site.

Continue reading The Union Pacific Type – Building a Steam Locomotive in LEGO

Taking it to the next level – Corfe Castle Station

After the previous post on Ararat 1972 and Cale’s piece on Brick Model Railroading as such, I think the pieces are now set for the next installment in the series of inspiring layouts: Corfe Castle Station by Carl Greatrix. Lately, Carl has been the guy who has brought you the Caterham Seven and a lot of the visuals in the recent Lego games, but next to this, he is also a real trainhead and a lover of Scale Modelling. With the Corfe Castle Station layout, he had decided to fuse both of these to create an unique layout.

Corfe Castle Station – the eye-catcher and starting point of the layout
The (almost finished) layout at STEAM 2011

The first thing that you notice when looking at Corfe Castle Station is that it follows a typical “British” approach. At least, that’s how it looks like for me after having read so many British Model Railroading Magazines (like Railway Modeller) when I was young. This means that we are looking at two mainline tracks and a siding, with a station as the main visual element. In fact, it’s just a very big diorama. The layout is an oval of which more than half is the fiddle yard and thus not part of the diorama. So, just as with Ararat 1972, there is no large yard where you can show off your trains. However, it does have two continuous loops which are ideal to show of your trains in high speed!

Overview of the layout – Two ovals and a fiddle yard.

What sets this layout apart of most other Lego Railway layouts is the design choices he makes: instead of using studs everywhere, Carl uses Scale Modelling techniques for making roads, gravel and mountains. This means that not everything in this layout is made out of Lego! The effect works surprisingly well. Instead of looking like a layout made of Lego, this is a layout that uses Lego as one of its mediums.

An example of combining Lego with scale modeling techniques

It becomes even more interesting when inserting his trains. This is because Carl, unlike most Lego Train builders, tries to use as little selective compression as possible. The result are models that are so accurate, that they don’t even look out of place in an actual O-scale layout.

Carl’s trains in an O-scale layout. Not part of Corfe Castle, but too nice not to show.

As said, the layout not only uses Lego. Carl was nice enough to keep a diary over at Flickr in which he shows how he designed the whole layout.  This gives us the great possibility to dive a bit deeper into the layout and the way how it’s build.

Continue reading Taking it to the next level – Corfe Castle Station

Are we real model railroaders?

When I woke this morning I had planned to write an article about a very different subject. But upon opening my Facebook feed I was greeted with a post I made on my wall 5 years ago, concerning the topic of “Are LEGO® Trains considered real model trains?” The post was spurred by a Eurobricks discussion going on at that time. Bellow is my entire post on the subject from January 2012 (excuse the typos). I found it very interesting to see what my thoughts on the LEGO train hobby were back then, compared to where we are now.

Continue reading Are we real model railroaders?