Dynamic Load Variation and Refuelling

Aim - This page aims to describe how to define the parameters for animation of loads, the loading/unloading of trains, such as tender coal in a steam locomotive, grain and coal wagons, as well as the types of tests that can be undertaken to ensure that it is operating within realistic bounds. It also describes the ways of refuelling the locomotive.

If you wish to provide any feedback on this page, please use the contact page. It would be great to have some feedback as this helps to ensure the accuracy of the information and models.

Index

Introduction

Route Pickup Points

Wagon Definition

Locomotive and Tender Definition

Picking Up Water from Track Trough or Pan

Key Parameters Used in Open Rails


Introduction

Open rails supports the functionality to load and unload trains, as well as the ability to refuel the locomotives with either coal, water or diesel. This functionality can be further enhanced with moving animations, so that for example, the coal loads in a tender can rise and fall depending upon normal usage, as well as refueling.

Additionally locomotives, will have their weight and related physics charisteristics change as they use consumables such as coal, water, diesel, etc, and wagons physics characteristics will also change as their load varies. The key physics parameters that will change with load are BrakeForces, Friction (Resistance), Weight, Centre of Gravity, and Drive Wheel weight on locomotives. Variation of wagon physics with load relies on having two known points of reference, ie the conditions when the stock is empty, and the conditions when the stock is full (loaded).

Wagons can be set up for one of the following modes of load operation:

  • Static - in this mode the freight animation is only loaded at the commencement of Open Rails and does not change during the game. Whilst multiple freight animations can be added to a vehicle, it is suggested that only one has "loaded" physics parameters associated with it.
  • Dynamic (continuous) - this allows wagons to load and unload during the game. In this mode there maybe a linked freight animation shape which moves as the load rises and falls, such as the case where an open wagon is filled or emptied. In the case of, say a covered van, there maybe no freight animation shape file used. It should be noted that locomotives and tenders only use the continuous freight animations for defining physics parameters, IntakePoints are defined instead in the general ENG file, and not as part of the freight animation.

To successfully set up load variation and animation functionality it is necessary to:

  • Step 1 - Create relevant pickup points within the route,
  • Step 2 - Configure the relevant wagons to allow loading and unloading at relevant pickup points on the route, define loaded and unloaded physics characteristics.

The test the loading/unloading process a demonstration activity has been created to show how a route, and stock can be set up to load and unload, with in this example, a coal train.

Whilst this page has been developed specifically for steam locomotives, a diesel locomotive could be substituted for the steam locomotive to test fuel diesel refueling and load variation, etc.

The following sections provide a "worked example" of setting up the load/unloading feature within OR. Also refer to the Open Rails manual.

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Route Pickup Points

Open Rails currently supports the following pickup points for loading/unloading, and refueling:

Load Type

Type #

OR Name

Comments

Null

0

Freight - Grain

1

FreightGrain

Freight - Coal

2

FreightCoal

Freight - Gravel

3

FreightGrvel

Freight - Sand

4

FreightSand

Fuel - Water

5

FuelWater

Fuel - Coal

6

FuelCoal

Fuel - Diesel

7

FuelDiesel

Fuel - Wood

8

FuelWood

Fuel - Sand

9

FuelSand

This is not an option in MSTS

Freight - General

10

FreightGeneral

This is not an option in MSTS

Freight - Livestock

11

FreightLivestock

This is not an option in MSTS

Freight - Fuel

12

FreightFuel

This is not an option in MSTS

Freight - Milk

13

FreightMilk

This is not an option in MSTS

Special - Mail

14

SpecialMail

This is not an option in MSTS

As indicated above some of the load types are not supported generically by MSTS Route Editor, and therefore some text file editing may be required to support the inclusion of the non-MSTS load types into OR.

For a detailed description and example of how to add Loading/Unloading and Refueling points to a route see the section titled, Pickup Points for Loads and Refueling.

For a working example of Loading/Unloading and Refueling points see the section below, Load Variation Demonstration.

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Key Parameters Used in Open Rails

The key parameters that define load animation in Open Rails are described on the following web page.

Standard Load Animation Parameters for WAG Files (updated June 2019)

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Wagon Definition

Whilst the FreightAnimation and filling information can be inserted directly into the WAG file, it is recommended that an INCLUDE file is created with the relevant animation and filling information. Typically the filling information in the WAG file will be aligned to the type of pickup point that the wagon is designed to work with. The following configurations are based upon the use of an INCLUDE file. To use an INCLUDE file, a folder called OpenRails will need to be created under the root stock folder.

A static and dynamic worked example are provided in the animated test stock.

Static Load

As indicated above a static load will only be loaded when OR initially starts. OR will use the base WAG file for the empty conditions, and the INCLUDE file for the full (loaded) conditions. The following code block demonstrates the coding of a static freight load.

include ( ../ctn_test_static_animation_wagon.wag )

Wagon (
ORTSFreightAnims
(
MSTSFreightAnimEnabled (0)
WagonEmptyWeight(6.5t-uk)

FreightAnimStatic
(
    SubType(Default)
    Shape( ..\\common.Loads\\15ft_open\\15ft_3p_HumpSheet2.s )
    Offset( 0, 0, 0)
    FreightWeight( 9.0t-uk )
    Comment ( No load compensation fitted - assume same braking force as empty)
    FullMaxBrakeForce ( 19.43kN )
    FullMaxHandbrakeForce ( 6.477kN )
    Comment( Assumptions - speed - 60mph (100.0km/h), Friction Bearing, 2 axles, frontal area - 6.0m2, Wagon Weight - 15.75 ton (metric))
    FullORTSDavis_A ( 358.37 )
    FullORTSDavis_B ( 7.7739 )
    FullORTSDavis_C ( 0.718740 )
    FullCentreOfGravity_Y ( 1.8 )
)
)
)

Code Notes:

Dynamic Load

As indicated above a dynamic load will cna be load/unloaded at appropriately defined pickup points throughout a route. The known full and empty physics information is all obtained from the FreightAnimation details. It is suggested that the base WAG file be set for either for the empty conditions. The following code block demonstrates the coding of a dynamic freight load.

include ( ../ctn_test_animation_wagon_coal.wag )

Wagon (
ORTSFreightAnims
(
    MSTSFreightAnimEnabled (0)
    WagonEmptyWeight(10.0t-uk)
    EmptyMaxBrakeForce ( 29.892kN )
    EmptyMaxHandbrakeForce ( 9.964kN )
    Comment( Assumptions - speed - 60mph (100.0km/h), Friction Bearing, 4 axles, frontal area - 5.8m2, Wagon Weight - 10.16 ton (metric))
    EmptyORTSDavis_A ( 580.71 )
    EmptyORTSDavis_B ( 5.0148 )
    EmptyORTSDavis_C ( 0.694782 )
    EmptyCentreOfGravity_Y ( 1.41 )
    EmptyORTSDavisDragConstant ( 0.0012 )
    EmptyORTSWagonFrontalArea ( 62.5ft^2 )
    IsGondola(0)
    UnloadingStartDelay (5)

FreightAnimContinuous
(
    IntakePoint ( 0.0 6.0 FreightCoal )
    Shape(H_Coal.s)
    MaxHeight(0.1)
    MinHeight(-0.85)
    FreightWeightWhenFull(26.0t-uk)
    FullAtStart( 0 )
    FullMaxBrakeForce ( 89.676kN )
    FullMaxHandbrakeForce ( 9.964kN )
    Comment( Assumptions - speed - 60mph (100.0km/h), Friction Bearing, 4 axles, frontal area - 6.2m2, Wagon Weight - 36.57 ton (metric))
    FullORTSDavis_A ( 748.61 )
    FullORTSDavis_B ( 18.0157 )
    FullORTSDavis_C ( 0.838530 )
    FullCentreOfGravity_Y ( 1.8 )
    FullORTSDavisDragConstant ( 0.0005 )
    FullORTSWagonFrontalArea ( 62.5ft^2 )
)
)
)

Code Notes:

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Locomotive and Tender Definition

Locomotives and tenders are treated slightly differently to wagons. The main difference is that IntakePoint information is not included in the FreightAnimation section of code, but in the base ENG or WAG file. Once the FreightAnimation code is added the locomotive and tender will vary their physics depending upon fuel consumption. Apart from this difference, all the other aspects apply in a similar fashion to the above. section.

The example locomotive setup for a locomotive and tender fitted with load variation is H6a Consolidation - #1499. Relevant specification information used for defining this locomotive can also be found by clicking on the link.

The following code block provides an example of that used for a locomotive or tender:

include ( ../USRA-Tender.wag )

Wagon (
ORTSFreightAnims
(
    WagonEmptyWeight( 28.75t )    Comment( 57500lbs )
    EmptyMaxBrakeForce ( 29.892kN )    Comment (Assume empty weight of 62.41t us)
    EmptyMaxHandbrakeForce ( 9.964kN )
    Comment( Assumptions - speed - 60mph (100km/h), Friction Bearing, 4 axles, frontal area - 12.075m2, Wagon Weight - 26.08 ton (metric))
    EmptyORTSDavis_A ( 682.19 )
    EmptyORTSDavis_B ( 12.8726 )
    EmptyORTSDavis_C ( 1.446464 )
    EmptyCentreOfGravity_Y ( 1.41 )

FreightAnimContinuous
(
    FreightWeightWhenFull( 42.725t )
    FullMaxBrakeForce ( 190.771kN )    Comment (Assume full weight of 71.475t us)
    FullMaxHandbrakeForce ( 9.964kN )
    Comment( Assumptions - speed - 60mph (100km/h), Friction Bearing, 4 axles, frontal area - 12.075m2, Wagon Weight - 64.841 ton (metric))
    FullORTSDavis_A ( 929.27 )
    FullORTSDavis_B ( 32.0042 )
    FullORTSDavis_C ( 1.446464 )
    FullCentreOfGravity_Y ( 1.8 )
)
)
)

Code Notes:

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Picking Up Water from Track Trough or Pan

Typically the early steam locomotives had tenders attached that gave them an approximate range of 40 miles before they needed to stop to replenish their water supplies. These stops added to the overall journey times of the train. and as pressure was put on railways to speed up trains operations and reduce journey times, the idea of picking up water whilst on the move was developed in the UK, USA and France. This eliminated the need to use tenders with bigger water capacities on them. Hence the use of track water troughs, or water pans as they were know in the US was born. For a more detailed description of water troughs refer to this article.

Tender Water Scoop

In regards to the operation of the water scoop the train crew lowered the scoop whenever the train was over the trough, and provided the train was traveling at a sufficient speed (Usually in excess of 15 mph) water was forced up the scoop into the tender. The above diagram provides a representation of the arrangement of a typical water scoop.

The minimum speed was typically determined by the height of the water scoop above the pickup point ( the distance h shown on the above diagram). The amount of water picked up by the scoop was determined by the area of the scoop immersed in the water trough, and the length of time that it was lowered into the trough.

OR models this functionality using a default set of dimensions. If the modeller knows the dimensions of the locomotive that they are modelling they can enter the following parameters into the ENG file.

The locomotive also needs to have a controller defined using the parameter WaterScoop in the EngineControllers section of the ENG file.

The table below indicates some of the typical dimensions for water sccops and troughs on different railway companies. These figures can be used as a guide if it is desired to customise the sccop dimensions in OR. Note that the water scoops used in the US were typically larger then those used in the UK. OR defaults to a medium sized scoop (somewhere between a US and Uk sized one). (Default - Width = 1ft, Depth = 3.5ins, Height = 9ft)

Railway

Scoop Width (ins)

Scoop depth below rail level (ins)

Trough water surface above rail level (ins)

Scoop depth in water (ins)

London and North Western Railway (LNWR)

10.0

1.0

2.0

3.0

Lancashire and Yorkshire Railway (LYR)

10.0

1.0

2.0 (steel)

3.0

Midland Railway (MR)

10.0 - Approx 9in @ base and 11in at water surface

0.75

1.5 (steel)

2.25

London, Midland and Scottish Railway (LMS)

10.0

1.0

2.0 / 1.5

3.0 / 2.5

Great Northern Railway (GNR)

10.875

1.5

1.0 @ Werrington, Muskham (wood), 2 @ Scrooby (steel)

2.5 / 3.5

North Eastern Railway (NER)

11.0

1.0

1.25 / 2

2.25 / 3.0

Great Eastern Railway (GER)

10.0

?

?

?

Great Central Railway (GCR)

10

0.5

?

?

London North Eastern Railway (LNER)

10.875

1.5

As per GNR / NER / GER / GCR

?

Great Western Railway (GWR)

11.875

1.0

1.5 (steel)

2.5

BR Standard (inc Diesels)

10.0

1.0

As per LMS / LNER / GWR

?

New York Central (NYC)

14.0

6.5

-2.0

4.5

Pennsylvania Railroad (PRR) Atlantic (4-4-2) Locomotive

12.5

?

?

3.5

Ouest / Etat / SNCF

?

?

?

?

Water effects are also able to be configured in the wagon section of either the ENG file if the water scoop is fitted to the locomotive, or the WAG file if the water scoop is fitted to a tender. See the Visual Effects page for a description of how to apply the WaterScoopFX and TenderWaterOverflowFX parameters.

A demonstration activty shows how this feature works, and the relevant pieces of stock used in this activity provide an example of how to set up this feature.

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