ADVICE, TIPS and copies of H-D instruction leaflets

First of all, here are the standard instructions that came with all Hornby-Dublo train sets, and those are still a good starting point for basic advice on assembly and maintenance: Instructions for Running Hornby-Dublo Electric Trains 1951

Other instruction leaflets:
Layout design suggestions
Power control Unit A3
Controller
C3 Controller
Electrically-operated points and signals
Colour Aspect signals
Isolating points
Isolating Rails
Electrically-operated uncoupling rail
Manually-operated uncoupling rail
TPO van
Grouping Rods for D1, D2 and G3 switches

(All Instruction leaflets courtesy the Hornby-Dublo Emporium)

INDEX
AIM
POWER SUPPLY
LAYOUT TRACK DESIGN
SETTING UP
TROUBLE SHOOTING
MAINTENANCE
COUPLINGS
SIGNALS
SCENERY
REFLECTIONS
CREDIT LINE

AIM
The aim is not to create a model railway, but a toy train set-up. A toy train can take liberties with scale and "vraisemblance" (looking like the real thing), that a model railway is not supposed to. Toy trains were designed for children, and their imaginations could be fired with just a hint of what was actually represented on the floor or the dining-room table.  That was their charm. But as toy trains went, Hornby-Dublo (and other H0/00 railways of its era) was also at the cutting edge of the metamorphosis from toy trains to model railways - and from that perspective is therefore of inordinate value in its place in the evolution of model trains as we know them today.

POWER SUPPLY
The purists will insist on the Meccano Ltd.-made transformer and controller. For those who will be satisfied with a good power pack, those made by Hammant & Morgan are an excellent choice, especially the "Powermaster" and the "Duette". Hornby-Dublo locomotives draw a good amp, and the H&M powerpacks work well. The six block sections that come with the "Powermaster" are a bonus. It should be noted that Hammant & Morgans are no longer made, but there are plenty of them on the after-market for somewhere around $20-$60. Just be sure you get a unit that hasn't had any amateur alterations and is otherwise in good working condition. If you buy one on-line in North America, be sure that you are getting the 120V export model. (H&M is a very durable product - I bought two "Safety Minor" packs new back in the 1960s, and they are still going strong.) One other tip: for those power packs that have the "wave" feature, run on "full wave"; and for those that also have the "resistance" feature, run on "low resistance". Half wave and high resistance create extra heat that is not good for the locomotive armatures. To prevent accidental use, cut out some small stout pieces of cardboard and push them into the open slide space.    

LAYOUT TRACK DESIGN
All toy trains came with what we describe today as "sectional track" - prescribed geometric pieces that (aside from end-to-end) will only allow for a defined configuration, such as a circle, "square" or "rectangle" oval, or figure-8 - or a combination thereof. The most usual was/is arguably the "rectangle" oval, and in Europe in particular with a double-track option, with sidings on the inside. Some makes came to offer elevated sections that could be configured into the "rectangular" oval set-up as an alternate running loop, and all manufacturers offered a variety of accessories that varied as to their "play-value" and their design with the age in which they were marketed. For instance, Bing and Märklin offered operating level (grade) crossings and train indicators, while Hornby 0 offered a system of mechanical signal operation, Trix-Twin a mechanical coal-loader and Hornby-Dublo a travelling post office mail bag pick-up and drop-off. In the toy train age, the emphasis was on running trains and incidental play value from the offered line of accessories, rather than on elaborate shunting (switching) or mock-timetable operation prevalent in the model railway era.

Pointers:

If at possible, go for a double-track design. Very definitely the signature of a European-prototype toy train set up. And it will simplify the eventual placement and operation of signals - see below.
Think very carefully about the siding space that you will require for both your inner and outer circuits, and plan accordingly. Remember that all siding space for the outer circuit has to come off "the straight", as H-D never made points for the larger radius. This means additional space on the outside of the outer circuit, and/or crossing over to or across the inside circuit for one or more inside sidings or loops (sidings with points at both ends).
Plan the number of "blocks" (on-off dead sections where you can hold a train or a locomotive), in the case of Hornby-Dublo, making the best use of the isolating points that switch the power in the direction of the set road. Remember though that isolating points have to have a power feed towards the toe of the point (the throw lever end of the point). Remember also that the electrically-operated points did not come with an isolating track version, so that one has to plan for any necessary "blocks" or isolating sections (see blow under "Electrical feeds to the Track").
Always have some extra track pieces to hand, so that when changes become desirable, you don't have to go back to your supply source before you can make the changes.
SETTING UP
Electrical feeds to the track
Hornby-Dublo provides straight and curved "terminal rails" that have posts for connecting the electrical feed wires. Inspect the posts carefully, especially the feed to the centre rail to ensure that the insulation is in good condition and has not become dislodged to make contact with the metal roadbed. H-D provides multi-strand wire, but for the short distances of most toy train layouts, solid-strand telephone-type SWG 22-24 wire will work fine. While terminal rails are always preferable, it is also possible to provide a centre-rail feed by tightly wrapping solid-strand SWG 22-24 wire around the centre rail "tongue" at the track connection, taking care that it is not too bulky, and that you insert an insulating tab above the tongue so that there is no possibility of contact with the metal surface of the roadbed.

Track connections
Before applying any track pieces to forming a layout:

inspect each piece to check that the centre rail does not touch the roadbed anywhere (slide a thin piece of card under the centre rail) and if found to be touching, raise gently with a small flat-head screwdriver.
check that the rails are not bent out of shape. If so, very gently bend back with both hands to as level a profile as the eye or placement on a flat surface will confirm.
check that the centre rail tongues are stable and the track joiners are tight to the rail. Over the years track joiners have taken a fair amount of abuse with the constant assembly and disassembly of track. A loose track joiner may result in poor or intermittent electrical contact. At points and crossings, tighten the joiner by pinching the sides with a medium-sized pair of needle-nosed pliers, but on ordinary rail lengths, preferably solder the offending track joiner to the rail. In either case, test the repaired joiner electrically before using. Alternatively, remove the loose track joiner altogether and substitute with a new track joiner typically available at hobby stores for H0 flexible track.
be sure to check that the centre rail tongues and the rail ends are clean and well-burnished for electrical conductivity. Tarnished tongues and rail ends can impede current flow or cause arcing. Burnish gently with very fine emery paper. If there is unexplained voltage drop that has no other apparent explanation, chances are this is the cause, and the only way to trace it is to isolate the section of track concerned piece by piece until the poor contact is found. The testing can mostly conveniently be done with a well-running 0-6-2 tank engine, running light.
Tracklaying
This is not intended to be a treatise on layout design, but these tips do assume that the layout is on a permanent base, there is a track plan, that electrical dead (block) sections have been decided on, and that thoughtful use is being made of the available track formations.
With these as "givens", here are some tips for good tracklaying:

the base must be as level as it is possible to get it
fasten the track at intervals with #2 slotted roundhead screws or #4 flathead or oval head Robertson screws
take good care that that the screw heads do not touch the centre rail (which will result in an immediate electrical short circuit)
do not tighten the screws so tight that they distort the metal roadbed at the screw hole, or distort the track piece altogether.
place screws at intervals just sufficient to keep the track in (straight) alignment
test the track being assembled electrically "as you go" to ensure that there is not an electrical short anywhere - do not leave it to the end of assembly to conduct your first test, as there is almost bound to be a "short" somewhere and you won't have the faintest idea where it is - meaning that you will likely have to disassemble everything that you have put together in order to find it.
ensure that each track unit is joined tightly to the next one.
make quite sure that each rail joiner has slid correctly into the adjoining rail so that there is no "bump" in the rail height, check each connection as it is made by running a finger across the top of the rails at the joint.
correct track "doglegs" - not only are they unsightly, but they may cause poor running and derailments
if the track plan is an oval double track, ensure that the track joints where the curved sections begin are exactly in alignment opposite each other, as otherwise this will create alignment problems if crossings or crossovers are subsequently inserted.
TROUBLE-SHOOTING

DERAILMENTS
If a locomotive or piece of rollingstock continuously derails at the same point - inspect the location carefully.
Possible causes in addition to under Tracklaying above:

(a) the track is not level there (insert a screw to level the track and/or place cardboard shimmy under track);
(b) for whatever reason the track is out of gauge (replace track piece);
(c) the track is not connected up properly at the rail joiners (reconnect the two pieces of track, ensuring that the rail joiners are in their correct locations),
(d) at the points or at a crossing, a guard rail may be out of position (gently correct with needle-nose pliers);
(e) the fault may be with the coupling or the wheel set (inspect equipment to ensure that couplings and wheel set are moving freely);
(f) the rails are out of alignment at the track joint (gently correct with needle-nose pliers - or file the two rail ends with a small Dremel-type hand file [taking care not to scrape the lithograph] until the inside rail ends are smoothly continuous);
(g) if it is a locomotive with the plunger-style pick-up in the tender (chances are there is not a smooth transition from one centre rail to the next - check the adjoining heights of the centre rail and adjust the one that is lower than the other by raising it gently with a small screwdriver blade while keeping your thumb firmly over the nearest fastening of the centre rail to the roadbed.)
SHORT CIRCUITS
If a locomotive refuses to move (not a stall on points or a crossing), or suddenly only moves very slowly, chances are that a short circuit has occurred. If you have a circuit tester, you can confirm it with that - the light bulb will only glow faintly, if at all.    

The first step is to shut off the power to all other track sections, one at a time.
If during that process the locomotive starts up and moves at proper speed, the problem is on the track section that you have just shut off.
Either way, once you have located the offending track section, check that

all electrical connections are tight
there is no metal, such as a derailed car, or a tool or other metallic object straddling the track
on a layout powered by more than one power pack, there is no conflicting polarity because of lack of insulation, or because a locomotive is straddling the crossing point and is stalled because of opposing polarities.
If that does not resolve the problem, place an 0-6-2 tank engine on the track, turn on the power to the slowest speed at which the locomotive would normally move and remove the fastening screws one by one, until the locomotive starts up; or if you are using a track tester, the light bulb starts to burn brightly.

Chances are that will resolve the problem. If it does not, start dismantling the track piece by piece working your way from the track piece furthest from the track section power feed towards the track where the feed is, with the locomotive occupying the track piece where the feed is. Once the offending track piece has been identified (see above under "Track Connections"), inspect it, make any necessary repair or adjustment, or replace the piece.

Now reverse the process in reassembling the track and replacing the fastening screws. Test the track with the locomotive as each piece of track and each fastening screw is put back.

Important note:  Do not leave a locomotive on a short-circuited track for any length of time with the power on. Even at a low speed setting, a short circuit generates heat that can eventually damage the locomotive armature and/or the power pack (if it is not equipped with a short circuit cut-out).

NO POWER OR LOCO DOES NOT MOVE (but no short circuit - see above)

Confirm that there is power at the track terminals at the section of track in question with a circuit tester
Check that the problem is not with the locomotive by checking to see that it runs on another section, or with feed wires to the wheels and pick-up from the track terminals
If there is power at the track terminals, test each section of track between the track terminals and the power outage
When the dead track section has been located, tighten or loosen the screws that pin the track to the base - chances are that heat or cold may have caused expansion or contraction that has dislocated the power feed
If that does not work, remove and inspect the dead track section for tight and clean track connectors, that the centre rail tongue is clean and properly aligned and tight, and that the connecting rails are clean at the webs. Also see under Track Connections and  Tracklaying above. If in doubt or if adjustment fails, exchange the track piece.
MAINTENANCE
Unless one has had the good fortune to acquire equipment and track that has been mint in a box for 60 years or more, one will be dealing with items that have been in use for that length of time, and will be showing the scars of having been well played with. Fortunately, Meccano Ltd. built "sturdy", and whatever has survived in working order until now, will likely continue to give remarkable service, if even moderately well looked after.

Cleaning
The enemies of all toy and model trains are dirt, dust and damp. Dust and damp can be avoided or at least minimized by choosing the right layout environment in the first place; but, yea verily, dirt shall be with you wherever you are.
One basic rule for dirt removal anywhere - do not use sandpaper-grade abrasives or strong solvents of any kind.

Dirt on wheels
Essentially dirt on wheels is the result of compacted dust, accelerated by humid air and any excesses of oilings that have found their way onto the running rails.
Dirt on locomotive driving wheels will cause stalling at the slightest provocation, usually over points and crossings.
For locomotives, consider a "Speedi" Driver Cleaner model 236 by Kadee (TM). Connected to a 12V  DC power source, the wire brushes will rotate the drivers while cleaning off the gunk.
Dirt on any wheels, especially on leading or bogie truck wheels, will cause derailments or uneven running with unwanted uncouplings.
For other than locomotive driving wheels, rotate by hand while gently removing the black gunk with a small Dremel-style screwdriver with the blade aligned flat to the wheel tread surface, being careful not to scar it. Also ensure that there is no remaining dirt at the edge of the wheel tread and the flange.

Dirt on locomotive pickups
This is usually remedied by a gentle wipe with a soft cloth. Stubborn gum can be removed with a drop of gentle solvent, such as Googone (TM), but be sure to wipe completely dry afterwards.

Dirt on locomotive commutators
The commutator is located on the worm gear drive shaft (the armature). It is usually kept polished by the carbon brushes against which it rotates, but if gum has accumulated, brush it off gently with a Q-tip. There are however 3 vertical slits in the commutator (on a 3-pole motor) that are inclined to plug up with a carbon deposit. Clean out the slits with a hair pin, but be very careful not to scratch the commutator surface.

Dirt on track surfaces
Newly-acquired used track can be gently scrubbed in nothing more than warm soapy water, and then rinsed and left to dry. This will not however likely remove corrosion and dirt on the rail surfaces themselves. There are any number of track cleaners on the market, but for Hornby-Dublo 3-rail I would recommend the CRATEX Abrasive Block XF distributed by Walthers, item 949-522. It's a little more expensive than the average cleaner, but does a great job of burnishing without leaving any grit at railside. Gentle on rail surfaces, but tough on dirt. When cleaning the centre rail, be careful not to exert too much pressure as this may distort that rail's alignment and/or even cause an electrical short if the supporting insulation bracket and tab are dislodged.

Oiling
These are the rules:
1. Follow the manufacturer's instructions in disassembling, oiling and reassembling the locomotive.
2. Do not over-oil. A little drop will do ya. Some seem to believe that if a loco isn't running too well, the answer is to add more oil. NO! The problem will be elsewhere. If you don't know what you're looking for, take or ship the loco to a qualified repair service.
3. Gently wipe off any excess oil.
4. Do not let oil get anywhere near the armature winding of a locomotive, or the solenoid windings of the electrically-operated points, signals and uncoupling rails.
5. Use a good quality sewing machine oil. (Use a hair pin to apply no more than a drop at a time.) Many modellers use Labelle 107 (medium) or 108 (light) with its convenient needle-tip dispenser.

To avoid damage to the body, a foam cradle, such as the one made by the Bowser Manufacturing Co., and available in all good hobby stores, is a good investment. Officially described as #22 H0 Scale Foam Loco Cradle.

It is a good idea to maintain a log of when the locos were oiled. How frequently that has to be done depends on the frequency of operation and the room temperature. If on inspection, the worm gear appears bone-dry, it's likely time for another drop of oil.

The rollingstock also needs occasional oiling attention at the wheels and the couplings. Carefully insert the needle-tip between the wheel and the body-frame to reach the axle bearing, with no more than one of drop of oil. Spin the wheels freely. Any bandy axles should be replaced. Likewise place one drop of oil at each coupling rivet, then wiggle to and fro until the coupling moves freely.