About this Website
The purpose of this website is to encourage use of on-board battery power and radio control of locomotives (and similar traction equipment) modeled in HO, On3, and On30 scales. Combining on-board battery power and radio control has two major benefits:
What is S-CAB?
S-CAB is a set of components to implement battery powered, radio controlled HO-sized model trains. Two technologies are involved:
A hand-held wireless controller (the S-CAB throttle) communicates directly with a radio receiver installed in a loco. Commands transmitted by radio control a DCC decoder powered by an S-CAB onboard battery power supply.
BPS (current version, BPS-v4), which is a core component of an S-CAB installation, provides an 11 volt, 1 amp power supply from a 3.7 volt battery. In addition to voltage conversion, BPS-v4 performs battery charging, safe battery management, battery on/off control, and overload protection; all within a small package.
Who may be interested
This website is for model railroad modelers and operators. I'm not an evangelist for new technologies or products. Quite the opposite; I'm an advocate for the simplest, most reliable, proven way to operate a model railroad.
S-CAB does not reinvent model train control. It builds upon, and is compatible with, existing model railroading products and standards, including NMRA standards for Digital Command Control (DCC). However, S-CAB is not DCC and does not require DCC equipment except for decoders, which are used for loco control.
Several obvious questions
Why use DCC decoders?
Because they're mature products with comprehensive model railroading functionality produced in vast quantities by many manufacturers. Development costs have long since been recovered and economies of scale give competitive advantage to established suppliers.
Communication to decoders is by radio?
Yes, for NCE and SoundTraxx decoders, the S-CAB receiver delivers DCC commands directly to the decoder's microprocessor. This is called "direct radio connect" (DRC) to distinguish it from the indirect method of using a DCC booster to convert radio data to DCC power.
What about other manufacturers' decoders?
Using a DCC booster is not as efficient as the direct radio connect, but works for most decoders.
Is a DCC system required?
No, a DCC system is not required. An S-CAB throttle transmits decoder commands directly to locos with S-CAB receivers.
Is S-CAB compatible with DCC?
Yes, output from DCC command stations or throttles can be transmitted by S-CAB radio. It can also remain connected to track in order to operate locos without S-CAB radio. Where available, DCC track power can be used by S-CAB BPS for battery charging.
Can S-CAB be used with DC layouts?
The answer depends on equipment being used for DC control. If track power is used for BPS battery charging, a well-filtered DC supply between 12 and 13 volts is an ideal power source. Unfortunately, legacy DC voltage controllers often deliver unregulated output with voltage peaks (spikes) that can damage electronic equipment. BPS-v4 can survive voltage peaks up to 30 volts, but it's best to avoid use of old DC loco controllers, especially models with "features" such as "pulse power".
Getting started with S-CAB
A decision to use battery power is not easy. S-CAB components are available to fellow modelers but determining what will fit and operate successfully in a selected loco requires serious conbsideration.
As I commented in a 2020 update, S-CAB components have iterated through several development cycles, reached a stable level of maturity and accumulated a solid base of user experience. They are a proven set of components for on-board battery power and radio control of HO On30, On3, and some S-scale models. 2020 was a busy year for development, which is now summarized under "News"
August 2021: This is a major website update. In addition to revising this "Home" page, a "News" tab has been added for quick access by visitors who are familiar with S-CAB. "Battery Power" and "Radio Control" tabs link to basic information for education/reference. "Price List" is most frequently visited S-CAB page. Some time will be required to implement changes, but the plan is to make "Price List" the go-to tab for S-CAB inquiries. Both Contact and Order Forms are moved under "Price List" tab. Future website maintenance will concentrate on "Home", "News" and "Price List" pages plus occasional additions to "Neil's Blog". Blue tabs on the navigation diagram link to relatively stable information that does not require frequent updates.
On-board battery power and radio control are separate, compatible systems. For example, a loco can be controlled by radio while being powered from the track. This is not a particularly useful application of radio control because it fails to solve the basic problem of unreliable electrical contact between track and wheels.
If S-CAB is used for both on-board battery power and radio control, four components must be installed in the loco:
Component widths are designed to be less than 18 mm (0.7") to fit HO-scale GP-class diesel locos. When appropriate, these components can be mounted vertically on edge in steam loco tenders. Since a battery is generally the largest component, its position frequently constrains the overall installation plan.
For suitable diesel locos, an S-CAB motherboard is the newest and easiest method of installation.
BPS Battery Power Supply
S-CAB BPS combines a battery charger, battery management and a step-up voltage converter in one package.
It performs the following functions:
S-CAB Loco Receiver
An S-CAB loco receiver is a radio module packaged with a DCC decoder such as the SoundTraxx sound decoder illustrated above. One unique characteristic of S-CAB is direct connection of radio receiver data to the decoder's microprocessor. This shrinks overall package size and avoids inefficiency of using a DCC booster to convert radio data to DCC power for input to decoder's left/right track connections.
A wireless, battery-powered, hand-held controller completes the S-CAB system. Communication is direct from throttle radio transmitter to a compatible receiver in the loco to which a command is addressed. Each throttle can manage up to 15 locos during an operating session. The throttle's radio is only active while transmitting a command (approximately 0.04 seconds). Consequently, operating sessions with multiple participants and up to 6 active throttles is possible without noticeable interference.
What is a Motherboard?
A motherboard (MB) is a circuit board onto which various components are mounted. Connectors and circuit traces on motherboard eliminate wiring between components. Terminals are provided for connections to loco motor, lights, speaker and battery charging input. In some cases lights and speaker can be mounted on the MB.
Example: Motherboard installation in a HO-scale Atlas-Kato GP-7
The entire assembly, including lights and speaker, is mounted on motherboard. No wiring bird-nest, no wired connections to the loco body and six connections to the chassis; two for motor and two from each truck for power pickup.
References to various manufacturers and their products are scattered throughout this website. Their proprietary rights, trade marks, copyrights, etc. are acknowledged.