Improving the running lights of a Hattons 66


Although Hatton's impressive range of Class 66 locomotives incorporate a full set of running lights, their colour and intensity could be better. An attempt to improve some of the shortcomings is described below. The guinea pig for this project is the DB Schenker Class 66, which will be modelled as one of the small number of DB 66s fitted with the new Wipac lighting modules.

Each lighting module contains a LED headlamp and a combined front marker / rear light lens. Both headlights at the forward end of these locomotives are used simultaneously, but in addition to the main beam, they also have a reduced intensity dipped beam. The rear lights and front marker lights share the second lens within each light housing. These use LED technology to produce either a pure white marker light or a red rear light.


An earlier Colas member of the Hattons 66 Fleet, showing the original lights in operation.

The Challenge:

To produce much brighter pure white headlights, with a dimmable option (to replace the original Hattons warm white day or night headlights). Also to replace the original warm white independent rectangular lower front marker lights with an arrangement that combines a pure white marker or the red rear light, beaming through the original rear light lens. 


The Livery:

My original intention was to convert the DB Schenker livery into the latest DB Cargo scheme, with the large DB logo replacing "DB Schenker" on each side and an appropriate change to the loco number and format. However, the quality of the bodywork finish as received is excellent and I am not at all confident about achieving a clean removal of the original lettering and numbers, without compromising quality....... so I'll proceed with the lighting work and leave a decision on the final finish until later.


Hattons DB Schenker Livery 66 variant

Hatton's photo of the less detailed Bachmann DB Cargo Livery 66 offering


First, the Headlights:

Two issues reduce the intensity of the headlights: a) Inverse square law loss due to the distance of the source LED from the light pipe and b) Losses within the light pipe.

The plan is therefore to truncate the headlight light pipes and bond a new LED with transparent glue directly to the new end of the shortened light pipes. If this is not successful, plan B is to remove the remaining light pipe from the lens and to glue the LED directly to the rear of the lens..... although this will be trickier mechanically.

The procedure is shown in the sequence of photos below:


Showing the light pipe windows in front of the cab moulding

Showing the light pipe assembly with the cab removed


Extracting the light pipe assembly from the body moulding


Proposed light pipe assembly modifications

Showing a headlight lens with just the short vertical section of light pipe still attached. The light pipe was cut using a Stanley knife.

A pre-wired "sunny white" DCC Concepts Nano-LED is bonded (beaming into) to the exposed end of the remaining light pipe.

(The lens is held in a lump of Blu Tack, while the glue dries.)


After the glue has set, the LED is fired up using a suitable series resistor and DC power supply.

Light leaking out of the sides of the LED is minimised by careful application of black enamel paint.


Repeating for the other side. (This LED works fine but has a conspicuous solder blob, which might explain why the pack contained 7 LEDs rather than the specified 6?)


Showing the re-assembled light pipe enclosure. The LED wires are routed through the old headlight light pipe apertures in the rear of the enclosure.

Blu Tack is used to block the now unused light pipe apertures and also to provide temporary support to the rear of the headlight lenses.


In this photo, the light pipe enclosures have been re-fitted and cab mouldings re-installed at both ends of the locomotive.

The series resistors for each new headlight LED are glued to the inner side of the locomotive roof, and the interconnecting wires have been added.


Next, converting the original rearlights into dual rearlight / marker lights:

The original warm white headlight and marker light chip LEDs are removed from each of the original lighting boards. A thin plasticard strip is glued to the PCB just above the original rear light chip LEDs. Pure white pre-wired chip LEDs are glued to the plasticard insulator, as close as I dare to the original rear light LEDs. The new chip LED wires are soldered to the pads of the original marker lights at the top of the PCB (being careful to get the polarity correct.)

With the headlight LEDs now removed from the small lighting boards, there is no longer any need to re-use the plastic shroud moulding that was previously fitted over the LEDs, prevented light leakage between the lamp lenses.



Front view of modified small lighting board assembly


Electrical connections between the new headlights in the upper body shell and the chassis assembly:

Three wired connections are made to a small section of solder strip, glued to the top of the EM2 loudspeaker. The wire length is contrived to lay along the top of the chassis assembly when the upper body has been re-fitted.



Close-up of the solder strip


Headlight LEDs electrical circuit..... Resistors marked * are between 2k2 and 4k7, selected for equal brightness.


LokSound V5 settings for main beam and dipped beam headlights intensity:

The main beam function output level CV is set for maximum intensity (31) and the dipped beam CV, to 6. The views below show the head-on results, illustrating that the headlights are significantly brighter than in Hatton's original arrangement.

The new marker lights and original rear light LEDs successfully share the new dual purpose marker / rearlight lenses.  (The original rectangular marker light apertures were subsequently filled and painted black.)


Dipped Headlights

Main Beam headlights


Rear Lights


Stay Alive Super-cap:

To improve reliability, I've added a 6800uF AVX supercap, sourced from YouChoos DCC. These devices are rated at 15 volts maximum, which is often exceeded on DCC layouts...... So to be safe, I always fit a series resistor and zener diode to prevent the charging voltage exceeding 15Volts. Having just used up my supply of 14 volt 500mW zener diodes, this time I found some low cost 5V6 and 9V1 zeners on Amazon. When connected in series, a pair of these limit the voltage seen by the supercap to typically around 14.7 Volts, which works very well. I glued some thin plasticard to the top of the supercap just in case it comes into contact with the roof mounted components.


Supercap circuit glued to a plasticard deck, bonded to the chassis block. Electrical connections

are made to the common positive and ground solder tabs on the decoder.


A decision on a possible livery update:

The red bodywork colour is painted. It is not the colour of the plastic moulding. I'm not confident about a clean removal of the original DB Schenker logos without collateral damage to the red paintwork, without an appropriate touch-up paint supply, so despite obtaining DB transfers for the job, I've decided to leave the current DB Schenker finish in place.


The finished locomotive




The technique described above is a good way to make the headlight intensity significantly higher than is possible with the original Hattons lighting arrangement. However, quite a lot of work is involved and the electrical connections between the upper body and chassis assemblies further complicates assembly and disassembly of these parts. The simulated LED headlights can be successfully dimmed using the LokSound intensity CVs.

The new DB wipac lighting units in fact have a larger diameter marker / rear light lens than their headlight lens and the upper marker light is also a pure white LED unit, so my simulation is not entirely accurate, but it should add interest to my DB variant in the Hattons 66 fleet.



Supplier website links:
Hattons    Source of all Hattons Class 66 models.
YouChoos    Source for Stay alive super capacitor.
Digitrains    Source for blank ESU LokSound V5 MKL decoder (Sound software sourced separately from Legomanbiffo).
Roads & Rails    Source for EM2 speaker
DCC Concepts    Source for sub-miniature pre-wired Nano-LEDs


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