Double Headers

[DrewTheWordsmith]

I know two locos together (steam powered) would be used back in the day for extra power on a long/heavy train. I'm just curious as to how this translates into model railways, it's not something I've done myself.

 

Obviously different locos have different capabilities in terms of speed and pulling power etc so to my limited understanding, unless you have two well matched locos, surely there are risks in pairing up locos? Would a stronger loco be dragged by a weaker one and the motor strained? Would the weaker one end up being pulled beyond what it's capable?

 

As I say, it's a curiosity...

[STG]

I know some layouts have wired resistors for accurate speed matching, although many go down the DCC route, which allows you to match speeds more easily

[96RAF]

Some folk use a dummy loco - unmotorised - and hang it on the rake as a show only double header.

Some locos were lashed up on the front of the train for a heavy route/load but for a case where a bit of a oush was needed over the hill then a banking engine was used. This would simply run onto the back of a heavy train and boost it over the hill, slow down at the summit and run back into holding position ready for the next one. A system of whistle codeswas used as the push me now or thanks you can go home now.

[GWR 14xx Tank]

You can double head with, as you have said, well matched locomotives, with similar motors, like the Hornby 0-4-0's with the can motor, a worm gear, and a gear mounted on 1 axle. Because the gearing and the motor is the same, they would run at almost the exact same speed, the only thing I could think of that would make a small difference is weight.

 

As far as I know when I have double - headed, if a stronger locomotive pulls / pushes a weak one, the weaker one normally just wheelslips as the other pulls / pushes it along. As long as the wheels move round, and don't get stuck whilst the other loco pulls / pushes it around, it should be fine.

 

I would say that pulling power is only really inscreased with 2 similar matched locos. If one is just slipping, I would very much doubt that pulling power is increased alot - because the wheels are slipping and not gripping or providing any more traction.

 

14xx Tank

[JJ73]

Well Drew last year I bought myself a Blue Pullman from C'field Market on a Thursday & took it home & it didn't work  ☹️ then I hooked it up to 2 of my Steam Locos (My Evening Star & the Cock O' The North (Not being rude - that is what it is actually called!!!)) & then it kinda worked (the reason why it the Pullman didn't work was b/c it nod no pick on it & now I've got it fixed & now it works!!!  😀) I made a vid about it if you want to see..

Thank you in advance

[GWR 14xx Tank]

It might be useful to read here. There is some information about double, triple and quadruple - heading locomotives on DC (which I would guess you are using, seeing as this topic is not on the DCC Forum section). On the last page there is also a safety notice about putting power controllers under too much stress.

 

14xx Tank

[atom3624]

For the old-style Hornby / Triang locomotives I remember that spring pickup 'pinging' quite often and having to locate and replace it.

 

Al.

[DrewTheWordsmith]

Interesting, so it works in principle but if there is a significant power difference the weaker loco is just more for the stronger one to pull but without doing any harm. And yes I was thinking more in terms of DC.

 

Also apologies, should've just done a search!

[JJ73]

No need to 'apologies' - that's what we are here for - to help out others in our Lovely Hornby Forum Community of ours!!!

[The Duke 71000]

Drew...

I have done a few tests with various (modern) steam loco models for double/triple heading, and I found virtually no problems if the models are from the same manufacturer. Hornby double/triple headed tender locos, no problems. Bachmann loocs minor shoving/pulling with double heading, dependant more on the age of the models. Pairing Hornby/Bachmann locos, problems more likely, although not serious.  

 

Potential problems can also be exacerbated by the type of controller you use, there are a number of controllers on the market. I use Gaugemaster panel mounted types, and a couple of specialist Kentrol resistance controllers, which being reasonable quality present few problems. The maximum amperage setting of the controller can be a limitation, in that two locos obviously pull more power than one. Some basic controllers used to be set as low as 0.5amps, and would probably cut out if you doubleheaded with two larger locos.

 

A further problem with load/amperage limitations is now being exacerbated as some model locos now come with a number of extra electrical items inside (regardless of whether you use 12v DC or DCC), and these extra electrical items increase the power demand further. The problem is also further exacerbated as many modern coaches with interior lighting now also have capacitors inside, which can ramp up power draw to unacceptable levels. A Hornby Britannia with 12 Hornby Pullmans I registered drawing 4.5amps, which is bordering on dangerous on 12v DC layouts where a lighter type of wire can be used than with DCC. I found it was the new Pullman models, which now all have capacitors & various other electronics. I had to remove these items, and rewire the Pullmans to reduce the ampergae draw to a more acceptable 1.5 - 1.75amps for the whole train. Such a high draw, would prevent double heading, as normal controllers are not normally set for more than 3-4 amps.

 

I suggest you test your locos to find out which ones are happy together and which ones obviously are not. You're not likely to do any damage if the tests only last long enough (a matter of seconds) to see there is a problem !

The Duke 71000.       

[96RAF]

Good info there Duke. Too easy to forget about additional current drains like coaches, especially on DC layouts.

[81F]

 If you are double heading (either with DC or using the Double Header function to pair locos on DCC) both locos myst be fairly well matched. If not I would place the stronger/faster loco at the front. As I had seen a photo of a Dean 4-2-2 piloting a Cpunt 4-4-0, I thought i would try the same using the double headfer funstion, but kept getting derailments as the County pushed the dean single off hte rails (particularly arounf curves.

 

I would also add that seemingly identical locos can have quite different performance. For example one of my Hornby/Dapol Terriers will easily gain 2 foot (600mm) over another if started off at the same time on the same track but uncoupled

[LCDR]

The only problem I have encountered when using more than one model locomotive on a train relates to the older models which have metal couplings and which therefore have to be coupled the right way round to prevent a short circuit. This was a particular problem coupling a Triang R153 0-6-0 Saddle tank with an R52 0-6-0T Fowler 3F. If you couple them chimney to bunker because of the way the chassis are arranged a short circuit is inevitable.

 

The Hornby Dublo / Wrenn Bo-Bo type 1 also presents a problem if you desire to operate them nose to nose as the prototype usually does, changing the couplings from metal to plastic solves the problem. I wired my together as well, to equalise the current collection, resulting in a remarkably powerful combination.

 

The Midland Railway was a great user of double heading, especially over the Settle & Carlisle, as too was the GWR in Devon and Cornwall where severe gradients needed a bit more 'welly'.

 

The Folkestone Harbour branch was another location where two or more locomotives would be used regularly on heavy trains. These were 0-6-0T of class R1 (as modelled by Hornby Dublo and Wrenn) , and might have two on the front and one on the back. When starting off the drivers would exchange "Crow" whistles to synchronise the moment of starting. There is a delightful Transacord record of this, followed by the bark of 3 locomotives tackling the bank. In 1959 some GWR 57xx panniers were drafted into Folkestone to replace the R1s which were getting worn out..

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 R1 class A174

 

Sometimes double heading was not necessarily for power but for providing enough steam to heat the carriages. The "Night Ferry" from Dover to Victoria had an L1 (or similar)  4-4-0 coupled on the front of the Merchant Navy so that they didn't run out of steam climbing to Sevenoaks.(or Farningham Road if routed via Chatham). 

 

The opposite way round occured when preserved Main Line steam needed to worked electrically heated stock on railtours. Some class 24 Bo-Bo were converted to Electrical Train Heatiing Locomotives (ETHELs) to provide power on cold days. These were marshalled between the the tender and the train. Nowadays an assisting diesel (class 47 commonly) is attached to the rear.