Railway Rules Which May Not Make Sense To Modellers...

[Mountain]

Some railway rules which are there for a purpose, may not make sense to modellers, but we need to remember that real railways have different weight ratios and things behave differently than our models do. An example of this is with our models, if we run a locomotive flat out round curves, it may hold to the rails ok, but if we then go to run stock behind it and do the same thing, we can find a model disaster as one coach or wagon may find the speed too fast and the curves too sharp and something comes off the track.
Now with real trains, running a locomotive on its own at speed can have issues where if it pulls something, it starts to behave itself. This is why on the real railways, locomotives running "Light" (On their own) have a 40mph max speed limit, but if these locos are pulling trains they usuallh have a much higher speed they are allowed to run.
Part of this is also due to braking. and where the weight it compared to how things handle.

But going back to models, anyone who has owned any of the 00 gauge Hornby live steam locos and tried them at speed will find the loco flies off the track, BUT put eight or ten free running coaches behind it and it runs so well one really has fun! On its own it is almost uncontrollable. It needs to pull a weight before it starts to behave, and it then really behaves once one has got used to it. Used to get almost triple the steaming minutes from mine than Hornby said it would do, but one had to ignore some of the instructions in regards of its control, as the little indicator lights were the exact opposite to what the instructions said they were!

Going back to the real railways, there are many rules which may not make sense to modellers, but if one works the real railways, things will make sense. The large majority of rules are due to safety. A few rules are to protect other senarios from happening which could be unsafe.

Thinking of track layouts into sidings where sidings were usually reversed into, and also headshunts provided so stray rolling stock would not roll onto main lines and cause an accident. Also other senarios where track plans were designed so steam locos would avoid entering into goods sheds as an example. Many older trackplans could not be worked by locos, but were worked by horse. But some senarions they were worked by locos from an opposite line using ropes and capstans, an aspect of mainline steam from the past (And early diesel) often forgotton about. When one sees the trackplans and then realises how they operated them, suddenly "Mystery" trackplans from the past make sense!

[centenary]

Not trying to turn this into a DCC v DC thing but, with DCC there are a couple of options for these scenarios. First one is you can limit the 'top' speed of any DCC fitted loco by setting one of the cv's. This stops kiddies who may play with your trains from whacking the controller on full and ending up on the floor. Note to self, set DCC locos grandson will want to use with a limited top speed!

Another option is to fit one of DCC Concepts slow speed \ ABC boards to track sections such as bends to automatically slow any DCC fitted loco entering the relevant section. Im not certain if any cvs on the loco decoder needs tobe changed or, the slow function is entirely controlled by the slow down \ ABC board(s).

Other manufacturers may have similar boards with the same functionality.

[Mountain]

Those live steam Hornby locos come with their own controller which must work in a command control way but with high amp output for running the live steam part, so even if they did run on the standard DCC protocols set up by Lenz, it would be of no practical value to limit the speed of the locomotive as it would just mean one would not be able to raise steam .. I no longer have it as it is one of the things I sold when I had no income in the past.

[Bigmet]

The Hornby live steam failure was in my opinion precisely because they failed to recognise that DCC was far and away the best route to take for control of this system, and also fully compatible with control of regular electric motored locos. 'Two birds with one stone' as the proverb has it. DCC inherently has both the required current supply capability for steam raising, and the robust and reliable fine control required to vary the boiler current supply and operate the motorised regulator. It was this aspect that control of Hornby live steam fell down on, reception of the control signals was unreliable resulting in slow response and runaways. Introduced properly integrated with DCC it might have survived...

Not trying to turn this into a DCC v DC thing but, with DCC there are a couple of options for these scenarios. First one is you can limit the 'top' speed of any DCC fitted loco by setting one of the cv's...

This is one of DCC's killer advantages in my opinion. The set of programmable control characteristics enables complete consistency: not solely limitation of top speed, but a dead slow creep in and out of motion, and standardised speed curves and accelerations. Unlike the past times preoccupation with constructing mechanisms with a suitable motor and gear ratio selection to deliver an appropriate on track performance; now we have a big electronic stick to make any brand's mechanism design - however wayward - operate exactly as the owner wishes.

My layout operates with above standard voltage for HO/OO, set so that there is 15V available at the motor terminals: that's to make some RTR OO sluggards that cannot get anywhere close to scale maximum speed belt along properly. (Have ECML main line layout, the express traffic will go scale speed fast to contrast properly with the slow unfitted freight.) I also have some RTR locos with loony gearing in the 4:1 to 8:1 range, which will achieve speeds scaling in the range 350 to 400mph+ on 12V DC. These are completely tamed by DCC (one has CV5 for maximum speed set at 28 out of the 250 step range!) and as a result they go about as they should.

...Another option is to fit one of DCC Concepts slow speed \ ABC boards to track sections such as bends to automatically slow any DCC fitted loco entering the relevant section. Im not certain if any cvs on the loco decoder needs to be changed or the slow function is entirely controlled by the slow down \ ABC board(s)...

This is (I believe) a Lenz originated system and requires decoders which detect the voltage bias on the track that the installed section hardware creates. Lenz and Zimo decoders have this 'ABC' capability, and quite likely other European decoder brands. Quite how to use it and whether any CV's have to be set on the decoders is outwith my experience.

However I have seen the effect, when I hooked up a DCC system to an old and very sophistimicated DC layout, and ran a couple of my Lenz decoder equipped locos, which slowed down and then accelerated unexpectedly. It turned out that the layout's one time automated signalling relied on diode matrices hooked into track sections, and these were still in place and acting to bias the DCC track voltage sufficiently to actuate the ABC system to some extent. (Neither I nor the inheritor of said layout took it further in the way of investigation.)

[mrobs2002]

This is why on the real railways, locomotives running "Light" (On their own) have a 40mph max speed limit, but if these locos are pulling trains they usuallh have a much higher speed they are allowed to run.

Eh? My information is that a loco with a max speed of 85 or less can run light at 60 mph, and 90 or more can go 75 mph.

[Mountain]

Was 40 in the rule book when I was working. Not that I ever needed to know that specific rule as a guard because as a guard I can't think of a sanario we needed to know except to know that the driver knew... (Not that they would appreciate beig told!) As a guard in those days, we were in charge of the train which included the driver. Rules later changed during my time where we then had less responsibilities than we used to have and drivers were given more, but also had a massive pay increase where we stayed the same for about three years when by then I left. (Wasn't for that reason at all. Pay was still more than enough for me).

[mrobs2002]

This is why on the real railways, locomotives running "Light" (On their own) have a 40mph max speed limit, but if these locos are pulling trains they usuallh have a much higher speed they are allowed to run.

Eh? My information is that a loco with a max speed of 85 or less can run light at 60 mph, and 90 or more can go 75 mph.

Sorry, it's the line speed that's important, not the loco's max. So if line speed <90 then a light loco can travel at 60, if line speed >90 then it's 75.

There are at least a couple of Youtube videos filmed from the cab of a light loco. It's definitely going faster than 40.

[Bufferstop]

Eh? My information is that a loco with a max speed of 85 or less can run light at 60 mph, and 90 or more can go 75 mph

This would seem to be a more likely limit on the loco, assuming the line speed was high enough. It accords with my own observations of Thunderbirds called in to action on the WCML.
Standing on a crowded through platform at Manchester Piccadilly the PA asked us to stand back (how) whilst a train passed through. It was a lone 66 making no concession to any speed limits which went to rescue an EMU at London Road, (The cause of the waiting crowds.) Within a few minutes the procession of delayed services began

[Phred]

I was standing on the platform at Flitwick station with my wife and kids in September 2000, the first time I had been back to the UK since my parents emigrated in the sixties. When an express train to London shot through at speed, it frightened the bejeezus out of us. We had never seen anything move so fast in our lives!

[Bigmet]

...When an express train to London shot through at speed, it frightened the bejeezus out of us. We had never seen anything move so fast in our lives!

Eventually the unhappy day will occur on which a fast moving train will derail adjacent a crowd waiting for a stopping service on a nearby platform, and it will be the 1952 Harrow accident all over again. Major outcry, and that will be the end of little control of passengers to railside infrastructure: admission to platforms will be restricted to defined 'safe' intervals when only the stopping trains moving at low speed will be operating through that station. (The real answer is the principle seen on many of the long established high speed train services around the world, dedicated routes, separated from the slower stopping traffic.)

[Mountain]

Whatever that can be done to reduce accidents and yet keep things running efficiently is money well spent!