The RailNet RailBoost 5

The RailBoost5 Power Booster is based upon the TMW-DCC TMW05 MidiBooster, a 1.5 Amp booster, and the TMW06 Power Supply.  I've modified it to a 5 amp booster with a larger power supply.  The booster currently DOES NOT have short circuit protection, and I recommend that you use it with a DCC Circuit breaker such as the Tony's Train Exchange PSOne.  Exposure to a short circuit for more than a few seconds will result in damage to some of the electrical components, and in some cases explosion of the silicon casings due to excessive heat buildup.

I've assembled several of these boosters for use on my layout and for friends.  Creating a system beyond the breadboard can be extremely challenging.  To assist, I've created circuit board designs for the two modules (the power supply and the booster) that can be uploaded to ExpressPCB.  The latest designs on this website have been upgraded to accomodate full 5 amp pathways from the power supply through the booster, however, I have not tested them as of yet, but will do so shortly.

(To utilize these designs, download the free software from ExpressPCB.)

Power Supply

The power supply accepts 12-15V AC input and provides 5 amps of +15V and -15V DC for the booster, as well as 2 amps of 5V DC for a few IC's.

Power Supply Schematic and PCB Design


The booster is connected to the outputs from the Power Supply and the transmit pin from the PC serial port.  The serial port signal is amplified and used to turn pairs of transistors on and off at high speed to create the DCC data signal.

Booster Schematic and PCB Design


The following is a listing of the components in the design and their Digikey order numbers to assist in ordering. 

BoardPart LabelDescriptionSourceOrder NumberQuantity
Power SupplyJ1Terminal Block - 2 PositionDigikey281-1414-ND1
Power SupplyJ2Terminal Block - 4 PositionDigikey281-1416-ND1
Power SupplyRECT1Rectifier - 100V 8ADigikeyMB81-BPMS-ND1
Power SupplyC1, C2Capacitor - 5600uF 50VDigikeyP6933-ND2
Power SupplyC3, C4, C5Capacitor - 470uF 35VDigikey493-1084-ND3
Power SupplyQ1Transistor - PNP TIP2955Digikey497-2608-5-ND1
Power SupplyQ2Transistor - NPN TIP3055Digikey497-2586-5-ND1
Power SupplyR1, R3Resistor - 1 Ohm 5WDigikeyTWW5J1R0E-ND2
Power SupplyR2, R4Resistor - 10 Ohm 5WDigikeyTWW5J10RE-ND2
Power SupplyREG1Voltage Regulator - 15V 1.5ADigikey497-1454-5-ND1
Power SupplyREG2Voltage Regulator - 5V 2ADigikey497-1468-5-ND1
Power SupplyREG3Voltage Regulator - -15V 1.5ADigikey497-1478-5-ND1
BoosterJ1Terminal Block - 6 PositionDigikey281-1417-ND1
BoosterJ2Terminal Block - 2 PositionDigikey281-1414-ND1
BoosterR1, R2Resistor - 200K Ohm 0.25WDigikey200KQBK-ND2
BoosterR3, R4Resistor - 330 Ohm 0.25WDigikey330QBK-ND2
BoosterR5, R6Resistor - 1K Ohm 0.25WDigikey1.0KQBK-ND2
BoosterR7Resistor - 0.47 Ohm 5WDigikey0.47W-5-ND1
BoosterIC1Op Amp - LF351Digikey497-2966-5-ND1
BoosterQ1Transistor - NPN BC337OSDigikeyBC337-ND1
BoosterQ2Transistor - PNP BC327OSDigikeyBC327-ND1
BoosterQ3Transistor - PNP TIP126OSDigikey497-2570-5-ND1
BoosterQ4Transistor - NPN TIP121OSDigikey497-2537-5-ND1
BoosterC1Capacitor - 0.047uFDigikeyP4307-ND1
Case Project CaseRadio Shack270-18091
Case Illuminated Rocker SwitchRadio Shack275-6921
Case 9 Pos. Male D-Sub ConnectorRadio Shack276-15372
Case Banana Jack Ins. Binding PostsRadio Shack274-6621
Case Stackable Banana PlugRadio Shack274-07341
Case Transformer 115VAC 12.6VCT 6ADigikeyHM5220ND1


Prior to using the board on your expensive locomotives, here are some simple tests to ensure the boards are working properly.  Please be sure to use safety glasses and gloves for your protection in case of failure.

Power Supply

Using a Voltmeter, measure the DC voltage from the outputs of the 15V, 5V, and -15V terminals.


Connect the serial input on the Booster board to the 5V terminal, then connect the Booster to the power supply, measure the output, it should be a solid 15V or -15V (depends upon how your have your voltmeter hooked up to the terminals).  Then connect the serial input on the Booster board to the Ground terminal (GND), the output should be the opposite of what you read previously.