creating frogs, is there rule of thumb?

[Justme Igor]

As the title is saying, is there a rule or rules to create frogs?
Dispite the fact the most companies have there own "design"(or am i complete wrong here)
Chinees, Dutch, German, Russian, Soviet, UK, US of A ect they all have there own
There are some things pretty similar in all there designs.
After "creating" some in pvc board and some 3d designed/printed frogs, i was wondering if there are some rule of thumb.

Despite the "look a likes" between frogs in some country's/companies/continents and even different periods, how do i know i dont do it wrong?
Most, if not all, frogs are made to fit on site and for that particular crossing/turnout/ect.
So this question is not really about flange or no flange bearing or the weight or speed of the trains that are running over them, or is this the big main factor to design a frog?

It is something i can not put my finger on it, i have accumulated over 250 pictures of different frogs of diamond crossings alone... i hope someone here can and is willing to explain this to me.

How does one create a frog, where to start?

Many thanks in advance, with best regards Igor

 

[Matt M.]

HI Igor,

That is a very simple question with a very long and involved answer.

Crossings change all the time. Things like bolts. The material used changes;
the number of bolt holes change; the spring washers change and it goes on and on.

While the style of manufacture the crossing will change from time period to time period
as manufacturing abilities and materials improve there are some basic things to look at.

In the style department with flat bottom rail you have various methods of bolting
the crossing together and then fixing it to a plate. Bolted and riveted. Welded.
And of course cast crossings.
This will vary depending on your chosen company and the period.

You also get gradual changes in flange way clearances to get better wear of rails.
The considerations during the steam locomotive era is also governed by this due
to the long rigid wheel base of engines. Diesel era crossings have less compromise.
Flange way gaps in the throat of a crossing get narrower over time as well because
wheel development is a continuing application of improved materials and manufacturing.

Designs of crossings are full of compromises as things like the flange way clearance and
wheel tread transfer are opposing considerations.

There are situations with small No. crossings and unavoidably wide flange ways due to angles
which means larger gaps in the transfer from wing to point. There you will find riser blocks for
the flanges to ride on between the two rail heads. These are known as floored crossings.

On smaller crossings you are also trying to avoid guttering. Worn wheels can chew out the
outside edge of the wing rails. You can use an easer rail on the outside of the wing rails to lift
the worn wheels onto the outside of the wing rail without shock.
Mainly needed in high traffic areas.

Standard or common crossings are catalogued. Replacing a standard crossing is easier as
it should just fit and work correctly as they are an exact duplicate.

Standard V crossings consist of four pieces of rail curved, set and machined for accurate
assembly with the parts secured in position with bolts passing through the rails and spacer
blocks. Or welded together. Or cast. Or sometimes a mix of these.

Point of intersection to nose depends on weight of rail.

Lengths vary with crossing number and the rail section.

Special crossings vary from the standard ones in the rate of slope, the length, openings,
flange ways, curvature and type of construction. Replacements will have to be ordered up
especially and very careful measurements will need to be taken from the crossing that is
already fitted. Most companies keep a listing of specials on a line with the dimensions
of the crossings laid out.

I don’t know how helpful this is Igor but hopefully it is a start.

Regards, Matt M.

 

[Justme Igor]

I don’t know how helpful this is Igor but hopefully it is a start.

Dear Matt,
This is very helpful, thank you for the time you spend on this article, very appreciated.
A lot of things you mentioned i suspected and a lot more important info i did not even realise.
This is a lot of food for thought for me.
It will help me greatly to improve the realistic look on my garden layout.

With best regards, Igor

 

[Matt M.]

HI Igor,

I'm glad it helps but it barely touches upon the subject. The basic decision on the size and
angle of a crossing is predicated on what the converging and diverging track angles and curves are.

The bigger the steam locomotive the longer the crossing required. And the faster the train is going
the longer the crossing required.

And also appropriate placement. See the recent discussion under a 1 in 5 or a 1 in 6 on the forum:

https://85a.uk/templot/club/index.php?threads/143

Model leads or turnouts are not accurate as the operating mass and weight of the real thing doesn't
scale down and the wheel standards bear no resemblance to reality unless you are modelling in
one of the more exacting scales like P4, S4, P3.5, S7 and such.

The length of a modern high speed lead is so long that it really can't be modelled by most people
unless they have space and money for a very, very large railway room.

If I can answer a more specific query about any of this let me know.

Regards, Matt M.

 

[Justme Igor]

Hi Matt,
Thank you very much for your answer, i will try to explane what i am up to, where i am atm and what i would like to achieve.
I don't think i am doing it that bad so far?
I am genuine interested, i also started for a certificate for railroad engineering at the university at Delft.

I think i have room (garden) enough to be semi prototypical.
The garden area is 100 by 60 meters, the house is somewhere in most south corner.
We have some goats on a connecting field incl 2 big sheds
The goat field is 20 by 150 meters long.(my wish to build Amsterdam cs from 1936)

On the outside edges of the garden there will be 3 "main lines".
In one of them, the smallest radii will be 4meter60
This one will get a wider gauge: 45.5 or even 46.5 mm.
It got to my attention that this happens also in the prototypical world.
On this line i intend to drive the biggest of the biggest, incl the AA20, Bigboy ect(building the AA20 atm)
The rest will have a minimum radii of 3 meters.

My smallest turnout will be 1:7.50. for the rolling stock/steam engines storage shed in and out.
By my "storage" shed the following up turn out to the big main line will be 1:9-1:10.
The diamond crossovers that i need will have a minimum radii of 5 meters.
I am building in p32 scale one, as exact as possible incl the wheels.
The AA20 will choke in smaller than 4,5 radii. Below 4 meters it will derail or jam at low speed.
This is/was with a test frame btw. still tweaking
The centre to centre will be 150mm due to 40, 50 and 60ft cars.(again: many thanks Martin for this heads up/warning!preventing disaster.)

I will try to explane the origin of my question what started this topic.
Because my love/childhood wish for the bigger engines, trains modelling and model railroad.(name one odd one: i think i have the drawings and or pictures on my hd),
I would like to have one(1) complete track dedicated only for them because the lack of room i have.
This track will go only on the outside except for one occasion.
It must cross the two inner lines, before it goes around the house.

So those frogs need to be adapted, i think, also to prevent derailment, but i would like to be as close as possible to prototypical.
All frogs will be flange bearing and the guard rails will be extended if i must.
Yes the joke is on me, the AA20 was a driving disaster.
I am busy for 1.5 years now and only 12 meters of test track in the garden, and some failed but knowledge gained experiments.

In the box file you can see what i am up to with my "headache" corner.
I build one with a 4 meter radii, as suspected it failed due to the radii.
I build also some scissor crossover with a radii of 4 meter 60, with low speed the aa20 will do it, but i must make the gaps in the frogs a bit wider.

So far so good? i would like to hear your thoughts about this if you have time ofcourse.

Ps i create all in a 3d program with a 3d printer in abs, yes i can be costly but it is more time consuming.
I can do all the changes needed that is why i am also questioning, my better half also like trains, for her the soviet emperor cars she likes very much.

Thanks in advance, with best regards Igor

 

[Phil O]

Hi Igor,

If I remember correctly there were problems with the peak class diesels 1Co-Co1s classes 40 to 46 under the tops system, derailing on crossovers and I think that the cure was to increase the length between the switches and the common crossing (frog), but I don't remember the exact details. When I get the chance I will Google it and see if that throws any light on the subject, or someone on here may have a better memory than mine.

 

[Matt M.]

Hi Igor,

You did pick one of the worst locomotives to run on your layout.
The real thing didn't like curves either. Nor was it good with crossings.
Does the model follow the prototype in having a fair amount of lateral
movement on the 1st, 2nd and 7th drivers?
Also flangeless tires on the 3rd, 4th and 5th drivers?

I'd be looking to use very long and straight crossings if possible with leads in and out
that match the length of the fixed frame of the engine.
Failing that have you thought of using a flyover?

Amsterdam Central Station. Wow. The station building alone would be something to see.
I assume you can get hold of the track work plans from the pre war period?
Then drawings of the preferred crossing construction method over the previous 10 years.
1936, was that post overhead catenary going in wasn't it? How are you planning to model that
outdoors?

Matt M.

 

[Justme Igor]

@Phil O
If you can find the time, i would be very interested.


The AA20 is indeed a big failure.
She spitted tracks, demolished every frog, frequent derailments, to heavy, could not keep the steam up and to make things worse, the soviet tracks where not up to the task due to the lack of maintenance.
If she was build 10 years later it would have been a different story.
If they sold it to the us of a and make the gauge narrower, it would probably still run.

Yes to all your questions.
I have all the video's that where made, pics, drawings, newspapers, comments, magazines ect.
In Russian German and some in English
What most people don't know, they where building two.
Originally build in empire Germany, altered in the soviet.
The Soviets did not pay for them, ect
Yes i do my homework always first and good, planning second, before i start

I'd be looking to use very long and straight crossings if possible with leads in and out
that match the length of the fixed frame of the engine.

What kind of length of crossings you where thinking about?
Could you explane leads in and out that match the length?
I am not sure if i understand this correctly.

The central station was in 1936 not yet electrified if i have this correct.
They started after the war with Amsterdam.
Some lines where electrified before the war.
From some air photo's i could also not discover some power lines.
The drawings i have are from a complete redo of the track work and even a small extension to the ash pit, coal and water supplies.
When i have time i will make pdf's of it and drop them in "resources".
https://85a.uk/templot/club/index.p...-amsterdam-cs-in-the-netherlands.89/#post-651https://85a.uk/templot/club/index.php?resources/amsterdam-central-station-1912.5/downloadI think you will like them

For drawings i have to make a appointment with the national railway archive in Utercht rail museum.
I must wait till the lockdown is over.

For Making that outdoor: using foam pvc sheets and 3d printed parts.

Thanks.

 

[Tony W]

Hi Igor,

If I remember correctly there were problems with the peak class diesels 1Co-Co1s classes 40 to 46 under the tops system, derailing on crossovers and I think that the cure was to increase the length between the switches and the common crossing (frog), but I don't remember the exact details. When I get the chance I will Google it and see if that throws any light on the subject, or someone on here may have a better memory than mine.

Hi Phil / Igor.
I am aware that the class 40 and 45 1Co-Co1s suffered problems with derailing on obtuse crossings in diamonds and they would have been restricted to longer types of turnout due to their long fixed wheelbase, with a minimum curve (without gauge widening of about 5 chains, or 100M). They were given a Route Availability of 7, which is among the most restrictive for Diesels locos. They were also banned from going over the humps in hump sorting yards due to their lack of vertical flexibility. The bogie frames were only allowed to pivot in the horizontal plane relative to the body and relied entirely on the axlebox springs to cope with any track irregularities. They also suffered with cracked bogie frames in part due to this.

Regards
Tony.

 

[Phil O]

Thanks for that Tony. I've not managed to turn up anything on the web, yet. I still need to work on wording the question.