Train Controls

Rail3dWiki — Train Controls

Some notes on different train control arrangements.

There are many different forms of train control and one day Rail3D might support them all. For the moment, and to support development of different control models, this page gathers information on different train types.


1 Diesel Hydraulics

1.1 Class 35, Class 52

Brush Electrical Controller positions:

  • Off (notch)
  • On (notch)
  • ¼ (notch)
  • ½
  • ¾
  • Full

Controller can be positioned anywhere between ¼ Position and Full Position, eg. half way between ½ and ¾.


2 Diesel Electrics

2.1 Class 20

Vaccum brake, not self-lapping


2.2 Class 25/2 25/3, Class 45

aei Controller Positions:

  • Off (notch)
  • On (notch)
  • -¼ (notch)
  • (notch)
  • -½ (notch)
  • (notch)
  • -¾ (notch)
  • (notch)
  • -Full

Controller can be in any Notch Position between On and Full Position. Field Diversion operates at On Position and beyond.

Vaccum brake, not self-lapping


2.3 Class 26, Class 44

Crompton Parkinson Controller positions:

  • Off (notch)
  • -On (notch)
  • -Full

Controller can be in any position between On Position and Full Position. Field Diversion operates at On Position and beyond.

Cl26: Vaccum brake, not self-lapping


2.4 Class 27

gec Controller positions:

  • Off (notch)
  • On (notch)
  • ¼ (notch)
  • Full

Controller can be in any position between ¼ Position and Full Position. Field Diversion operates at ¼ Position and beyond.

Cravens, self-lapping vacuum brake


2.5 Class 31, Class 46, Class 47

Sulzer engine, Brush Electrical Systems Controller positions:

  • Off (notch)
  • On (notch)
  • ¼ (notch)
  • ½
  • ¾
  • Full

Controller can be positioned anywhere between ¼ Position and Full Position, eg. half way between ½ and ¾. Field Diversion operates at On Position and beyond.


2.6 Class 66

Uses a an 8 notch throttle controller on a American style vertical control stand rather than a British style drivers desk. Unlike British locmotives the throttle is pushed away from the driver to increase power.


3 hst

3.1 Class 253, Class 254

Controller positions:

  • Off (notch)
  • 1 (notch)
  • 2 (notch)
  • 3 (notch)
  • 4 (notch)
  • Full

Note - there is no Field Diversion on hsts.


4 ac Electrics

4.1 Classes 81–87

Controller Positions

  • Off (notch)
  • Run Down (notch)
  • Notch Down (notch)
  • Hold (notch)
  • Notch Up (notch)
  • Run Up (notch)

Controller controls rate of Tap change - Run Up takes about 20 seconds from 0 to 100%, ie. about 2 Taps per second. Notch Up/Down moves 1 Tap Up/Down respectively. There are 38/39 taps. 1 Tap equates to 2.5%. A seperate “Notch Indicator” displays the current tap setting (0–100% and Weak Field)

Self-lapping brake with rhesotatic braking


4.2 hge 4/4 ii (mgb, Brünig)

Following derived from photos in H.B. Schönborn, Intercity Lok Re4/4 iv, Ch.3/4

  • On the left, lever (marked with arrows, not text)
    • Forward
    • 0
    • Reverse
  • In the middle, handwheel with off position at 12 o’clock, about 7 brake notches between 12 and 7.30 anticlockwise, 10 power notches between 12 and 6.30 clockwise (power notches are numbered, brake notches not).
  • On the right, three-position switch
    • Z (Zahnstange?)
    • E (??)
    • A (Adhäsion?)
  • On the far right are levers for the loco parking brake and train air brake.

The power electronics is controlled through microprocessors. It sounds as though the control position determines the te while accelerating, and the speed otherwise, but not clear how this works in practice. The brake positions on the handwheel control regenerative braking, with air brakes brought in automatically at low speed or if the buffer force gets too high.


5 dc Electrics

5.1 General

Traditional dc control systems using dc motors have starting notches, where current-limiting resistors are connected in series with the motors, and running notches, where the motors are connected directly to the traction supply. The starting notches can only be used for short periods while accelerating.

If there are two motors, usually there is one set of notches where the motors are in series (half the traction voltage each), and another set where they are in parallel. If there are four motors, there might be a series-parallel connection as well, with the motors in two groups of two.

Some trains also have “field-weakening” notches above the normal running notches — for these a resistor is put in series with the field coil, allowing the motor to develop higher revs for a given voltage.

In rheostatic braking notches, a resistor is connected across the armature. The field coil can be fed from the traction supply or a battery.


5.2 Old trams

Old (pre-1945) trams usually have a controller that allows the driver to select notches directly. The sequence would be something like:

  • Rheostatic braking (1–3 notches)
  • Off
  • Series notches (e.g. 1,2,3,full)
  • Parallel notches (e.g. 1,2,3,full)

There would be some sort of spring arrangement to help the driver to find Off, Full Series and Full Parallel.


5.3 Old mu stock

The driver’s switch doesn’t operate the contactors directly, but sends low-voltage signals to operate servos in the motor cars. In some systems the driver has direct control of the individual notches, but more commonly, especially on metro stock, the driver just selects “Series” or “Parallel” and there is a current-sensing relay on each motor car that notches up automatically when the current falls below a pre-set limit.


5.4 pcc Tram

(Designed in the usa in the thirties — the same control system was widely used in Holland, Belgium, Italy and throughout eastern Europe after the war)

One pedal makes it go, the other pedal makes it stop (!)

The control system adjusts the series resistance in very small increments according to the selected acceleration/braking level. If you push the brake pedal all the way down, it brings in mechanical track brakes and sanders, and passengers are disembarked through the windscreen.


5.5 Munich U-Bahn “A”

(Probably fairly typical for pre-semiconductor metro/light rail)

Mode switch

  • Rangierfahrt Rückwärts (reverse shunt) — sealed out of use
  • 0
  • Kuppeln (Coupling)
  • Rangieren (Shunting)
  • Serienschaltung (Series)
  • Parallel-Shunt (Series-Parallel)


  • 0
  • F (Feststellbremse - parking brake)
  • E1 (Electric braking)
  • E2
  • E3
  • E4
  • E4L

Power button (normally-off)

  • Aus (Off)
  • Aufschalten (notch up)

In use the driver selects the mode according to the desired speed, then presses the power button to notch up automatically through the acceleration notches. When the train reaches the right speed, the button is released to coast to the next station.


6 dmu

6.1 Various Diesel Mechanical units

1st Generation Diesel Multiple Units

Diesel engine with mechanical transmission (gearbox). See http://www.railcar.co.uk/mechanical/introduction.htm

  • Power Controller - Throttle control, similar operation and effect to car accelerator
  • Gear controller, Forward/Reverse lever and Four gears + neutral lever. See pictures (Esp at bottom of page) on http://www.railcar.co.uk/mechanical/controls/gears.htm
  • Non self-lapping brake
  • Gear ratios (typically)  1st - 4.28:1    2nd - 2.43:1   3rd - 1.59:1   4th - 1.00:1

See also You-Tube videos DMU Diesel Train Driver (4 parts)


7 Information requested

More information is sought (please add to this page), for example on the control arrangments for:

  • Modern diesels (eg class 66)
  • hst
  • Eurostar
  • European stock
  • us Stock
  • Underground stock
  • Trams

MRG 26/06/2013 14:46:43