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Author Topic: Reversing for a convoy having 2 steam engines at both side?  (Read 4172 times)

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Offline pwhk

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Reversing for a convoy having 2 steam engines at both side?
« on: October 01, 2013, 10:41:44 AM »
If the convoy has both engines at each side, I wonder why it still need reversing. Why not just have the train captain start the train in another end?

Also, it appears that both engine can power the train, giving the entire convoy more power, even the engines are in different direction. (Correct me if I am wrong, I am no expert in this matter)

Attached is the setup I am talking about. ;)

Offline wlindley us

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Re: Reversing for a convoy having 2 steam engines at both side?
« Reply #1 on: October 01, 2013, 05:23:35 PM »
The engineer still has to walk the length of the train, and check the brakes.

Offline jamespetts gb

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Re: Reversing for a convoy having 2 steam engines at both side?
« Reply #2 on: October 01, 2013, 10:20:33 PM »
The arrangement that you have shown was not typical: steam locomotives would only ever be used at the rear of trains for banking (i.e., temporary assistance for part of the journey up a steep incline; the rear locomotive would not be coupled to the rest of the train, and would be deliberately left behind when the train had reached the top of the incline). A rear steam locomotive was never used to expedite turnaround times.

Offline paco_m

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Re: Reversing for a convoy having 2 steam engines at both side?
« Reply #3 on: October 02, 2013, 09:21:32 PM »
In most countries in central Europe it was forbidden to do such things with steam locomotives because
1) they had no communication between a front and rear loco what can't work because both locos have to make exactly the same during the whole journey
when they needed additional locomotives (e.g. to climb up a hill) they always put all the locos together at the top of the train and used flags or whistle signals to tell the other drivers what to do
2) most waggons where not designed to be pushed at full speed

Offline Ves

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Re: Reversing for a convoy having 2 steam engines at both side?
« Reply #4 on: October 03, 2013, 04:29:59 PM »
But what if the case was to use the rear loco as a maneuvrecar (a car with a cab but no engine)? meaning that the front loco#1 is dragging the rear loco#2. When the train arrives At the terminal, the driver Shuts down the loco#1, walk down the train and power up the loco#2, make the braketest and drive away with loco#2 as the powersource. In some cases, both the locos are powered both ways where the teknik allows it.
Now this does more apply to electric and diesel locos, but its not possible with them either, why I'm writing this. :)

I know this method has been and is currently used in Sweden, and is called SMS-driving.

Maybe a way to tell which locos is allowed to be At the rear of a train, powered or unpowered, or is not allowed?

Offline sdog

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Re: Reversing for a convoy having 2 steam engines at both side?
« Reply #5 on: October 03, 2013, 07:25:36 PM »
But what if the case was to use the rear loco as a maneuvrecar (a car with a cab but no engine)? meaning that the front loco#1 is dragging the rear loco#2. When the train arrives At the terminal, the driver Shuts down the loco#1, walk down the train and power up the loco#2, make the braketest and drive away with loco#2 as the powersource. In some cases, both the locos are powered both ways where the teknik allows it.
Now this does more apply to electric and diesel locos, but its not possible with them either, why I'm writing this. :)

I know this method has been and is currently used in Sweden, and is called SMS-driving.

Maybe a way to tell which locos is allowed to be At the rear of a train, powered or unpowered, or is not allowed?

Locomotives are very heavy. A non-powered locomotive at the end of a train would put very large strain on the couplings. This rules it out for long trains where the strength of coupling limits it's load (reason for the banking engine at the back James described).  If the train was short, the additional mass of the extra locomotive would be significant and require the locomotives at both ends of the train to be excesively powerful. Which in turn would increase running costs.

It was in general not very practical even to put steam locomotives in series. They are constant force machines, slight difference in applied force would lead to very strong load unbalancing. It requires skilled crews on both engines to counter this. Which lead to very large steam locomotives, where one today would use double or triple head diesel engines instead. [Midland Rail did not follow that trend to large engines, which lead to its economic failure (and several severe rail accidents).]
(see Garrat, Mallet

Offline jamespetts gb

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Re: Reversing for a convoy having 2 steam engines at both side?
« Reply #6 on: October 03, 2013, 09:49:19 PM »
The technology was not really advanced enough in the steam era to allow what we would to-day call multiple working. Double heading was done (and, banking as described), but, in double heading the locomotives were next to each other at the front of the train where the drivers could see each other (and the signals) clearly, and in banking, the train was being pushed uphill relatively slowly and the rear locomotive was not attached.

A locomotive at each end of the train (or an unpowered driving unit at the rear) is common to-day with modern multiple working equipment, of course. I should add that an imaginary steam locomotive with multiple working is perfectly possible in the code (set it to "can_lead_from_rear=1" in the .dat file), but this is not implemented in the pakset because, for the reasons given, it is not realistic.

Offline greenling

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Re: Reversing for a convoy having 2 steam engines at both side?
« Reply #7 on: October 04, 2013, 04:59:44 PM »
Hello Jamespetts
in the uk was push and pull trains in the history not often in use.
But in germany was in the history the use from push and pull trains with steam engines possible. ::-\

Offline jamespetts gb

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Re: Reversing for a convoy having 2 steam engines at both side?
« Reply #8 on: October 04, 2013, 08:20:46 PM »
We had push/pull trains in the UK, with a steam locomotive in the middle flanked by carriages with cabs at the end, or a steam locomotive at one end and an auto trailer at the other. That is already represented in Pak128.Britain-Ex. We did not have trains with steam locomotives at both ends, save for banking.

If this practice was common in Germany, however, it should be possible to replicate in an appropriate German pakset using the .dat file parameter to which I refer above.

Offline sdog

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Re: Reversing for a convoy having 2 steam engines at both side?
« Reply #9 on: October 04, 2013, 11:00:14 PM »
German wikipedia mentions only Systems that are (i) similar to the autotrailer concept or use electrics on both ends. The examples for such systems were so recent, that i doubt very much a more sophisticated system, to control two steam locomotives over a distance, would have been tried earlier.

http://en.wikipedia.org/wiki/Prussian_T_18
Quote
The DB converted several Class 78s for push-pull running e.g. between Frankfurt and Wiesbaden. Because the engine driver in the driving coach could only work the brake, operation of the regulator and reversing gear was carried out by specially trained stokers as signalled by the engine driver. The last locomotives were retired by the DB in the mid-1970s at Rottweil locomotive depot (Bahnbetriebswerk or Bw).

Offline Ves

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Re: Reversing for a convoy having 2 steam engines at both side?
« Reply #10 on: October 04, 2013, 11:33:24 PM »
James, it is not possible at the moment to get the desired effect by putting can_lead_from_rear=1 in the locomotives dat-file. The moment you do that, the loco is impossible to run as singel loco, hence its doomed to only drive with locos in each end.
 I just tried (driving with only one loco with  can_lead_from_rear=1 in one end), and whats happening is for the first 2-3 times the loco reach a terminal, it uncouples and do the roundabout as its supposed to, but then it will start to reverse the entire convoi with whatever is in the end as the first vehicle. Something of a view when a long passenger service is 'backing' the entire way at full speed :P
I tried put can_lead_from_rear=0 in all the vehicles (the loco still had the value "1") but the effect remained the same.

Offline Milko

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Re: Reversing for a convoy having 2 steam engines at both side?
« Reply #11 on: October 05, 2013, 08:31:19 AM »
Hello

The steam engines have reverse but few of them can be used to produce power when traveling on the contrary

Giuseppe