in NL

Article in "De Ingenieur", issue 35, 1932

The first Garratt locomotive in the Netherlands

H. Brunner ME

In this article the reasons are mentioned that made the Limburg Tramway Co Ltd decide to purchase a "Garratt" locomotive. Furthermore a description is given of the acquired locomotive.

Some notes on this translation

This is a translation of the article that appeared in issue 35 of the Dutch magazine "De Ingenieur" (The Mechanical Engineer) in 1932. Some considerations apply.

I followed the UK English spelling.
Measures are as per original with the imperial measure in [ ] for the sake of our Anglophone readers.
Measures in imperial may be rounded to next logical level.
Measures and texts in the figures are as per original only.
Number notation follows the English / American custom, viz. a decimal point and comma as thousands separator.
Wheel arrangements are expressed in Whyte notation.
To the best of my knowledge there is no English nomenclature of Verhoop's valve gear. Based on the similarity of Joy's valve gear the names of Joy's equivalent parts where used approximating the Dutch situation as close as possible.
Brunner consequently refers to the power units as "draaistellen", bogies, a term which in the English realm is mainly used in the context of diesel or electric locomotives. I chose to retain Brunner's use of the term so bogies are to be interpreted as the steam powered engine units.
Due to space considerations the original article had a rather odd placement of tables and drawings in relation to the text. In this web publication tables and drawings are kept as close to the text as possible.

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General.

In December 1931 a "Garratt" locomotive of 71.5 t [70.4 long ton] service weight was put into service by the Limburg Tramway Co Ltd on her 26 km [16 mi] long line Maastricht-Vaals (fig. 1).

Fig. 1. The Garratt locomotive

In 1909 the Australian H.W. Garratt († 1913) obtained the patents on his engine type, with which the boiler was freely and completely accessible located on a frame that rested with pivots on a bogie each of which contained a separate locomotive engine. By locating the supply bunkers for water and coal on the bogie units, he diminished the tendency of the latter to rotate around their horizontal centers of gravitation at higher speeds as a consequence of the not fully counter balanced reciprocating masses of the components of the motion. Thus they contribute to the riding stability of the locomotive. He could increase the evaporative ability of the boiler almost at will because the dimensions of the boiler, the fire grate and the ash pan were no longer restricted by the tight dimensions and unfavourable restrictions of coupled wheels and water tanks. For every conventional locomotive he could make practically a double with at least equal road behaviour at a smaller weight and double tractive effort. This double locomotive with one large boiler worked more economical than two single engines with two small boilers. Moreover it saved on one crew. Until the year 1926 "Garratt" locomotives were exclusively produced in the foundries of Beyer Peacock & Co in Manchester and Société Anonymes de St. Léonard in Liège due to patent rights. The original Garratt patent has by now expired and locomotives to this system can also be supplied by other manufacturers.

The first "Garratt" locomotive was made in 1909 by the firm Beyer Peacock & Co and had serviceable weight of 33 t; the largest had until recently serviceable weight of 234 t [230 long tons]. Currently several hundreds of "Garratt" locomotives run all over the world, among others in Europe in England, Spain and Belgium and of the overseas territories for a major part in South Africa. Especially in recent times this engine type, which can be used for freight as well as passenger services and because of its symmetry in construction runs equally well both directions, has found a swift distribution due to its advantageous properties.

Considerations that led to the choice.

The locomotive described here is of the 0-6-0+0-6-0 arrangement, a four cylinder engine, and is designed for superheated steam of appr. 450 C [840 F] measured in the smokebox in the superheater header. She was made by Henschel & Sohn in Kassel (fig. 2).

Fig. 2. 0-6-0+0-6-0 "Garratt" Locomotive for superheated steam – 1435 mm gauge – 71.5 ton service weight. (CLICK image to enlarge)

For her choice the considerations applied that the "Garratt" locomotive is mainly beneficial on a railway line with small radii and severe grades. The line Maastricht-Vaals has these properties. The hardest curve to drive is S-shaped with a radius of 115 m [377 ft] for each of both curves; the steepest grade has an inclination of 20‰ over a length of 1500 m [0.93 mi]. The freight services on the line Maastricht-Vaals demand a locomotive with an adhesion weight of appr. 70 t [69 long ton]. The largest axle load permitted is 14 t [30,900 lbs]. Consequently the locomotive should have at least 5 axles.

Freight trains and on rare occasions also passenger trains were temporarily moved with existing 0-4-0 locomotives of 28.5 t [28.0 long ton] service weight in double heading. From a standpoint of safety and economics this was less than desirable. Moreover the number of available locomotives was hardly adequate.

The advantages that the "Garratt" locomotive offers in comparison to other design are now identified further as follows:

1)	The fixed wheelbase of the bogie units can be small; the jolts that are received by the heavy bogies as a consequence of unevenness of the track propagate only subdued to the boiler which is resting with its frame on both bogies on two central points by means of a ball shaped pivot bearing and socket; the center of gravity of the boiler, that in itself is already favourably low, shifts itself further inward in curves. Due to these properties the "Garratt" locomotive can drive through small radii better than any other articulated type and even with less than well laid track high speeds can be achieved.
2)	in curve transitions between inclined and level track the boiler takes the proper position without jolts;
3)	the boiler can be held relatively short and wide and is freely accessible everywhere due to the completely free location between both bogies; considering the decreasing evaporative capacity over their length the boiler's flues do not become undesirably long, while the firebox and the ash pan can be kept deep and of liberal dimensions; the latter will get only vertical sides. The air supply can occur easily over the entire grate area. A complete and calm combustion takes place on the grate, to which the fourfold exhaust of the cylinders contributes; the large passages of the numerous flues cause a good draft on the fire even without the necessity to maintain a high vacuum by a high and in itself unfavourable counter pressure on the cylinders; the thickness of the fire can therefore be small; the losses in the chimney are less substantial; the boiler is for these reason alone already a good and efficient steam producer;
4)	the short boiler diminishes the risk that the crown sheet of the firebox is exposed on steep gradients and suffers damage;
5)	the vertical load of the rails per linear meter is considerably more favourable than for other engine types. This was for the Limburg Tramway Co especially of value in association with the appr. 600 m [660 yd] long and averagely 20 m [65 ft] high Gulp valley bridge which is present in the line Maastricht-Vaals;
6)	maintenance is easier because all three constituent parts of the locomotive can be treated separately.

Finally the choice of a "Garratt" locomotive offered the Limburg Tramway Co. the big advantage that the chassis of the 0-4-0 locomotives with a serviceable weight of 28.5 t could be used. Only a third coupling axle had to be added. The middle axle has become the driving axle. The wheel on this axle have 5 mm thinner wheel flanges to negotiate curves easier. The main components like pistons, valves, drive and valve gear and running gear remained apart from some insignificant changes unaltered and therefore no separate supplies needed to be kept in stock. By raising the steam pressure from 12 [175 psi] to 13.5 kg/cm2 [195 psi] an almost identical ratio between largest tractive effort and adhesion weight could achieved with the "Garratt" locomotives as with the existing 0-4-0 locomotives. The drive gear had yet enough strength for this.


Fig. 3. Tractive effort diagram	Fig. 4. Power diagram

Main data

The main data of the locomotive are as follows

Dimension		Metric	Imperial
Gauge		1,435 mm	4 ft 8½ in
Steam pressure		13.5 kg/cm2	195 psi
Weight, empty with equipment		56,700 kg	125,000 lbs
Serviceable with half supplies, water level 100 mm [4 in] above crown sheet firebox		66,440 kg	146,500 lbs
Serviceable with full supplies, water level in boiler as above		71,450 kg	157,500 lbs
Adhesion weight		71,450 kg	157,500 lbs
Percentage of braked weight with full supplies with air brake		62 %
with steam and hand brake		62 %
Water supplies in water tanks		7,000 kg	15,400 lbs
Water supply in boiler (water level 100 mm [4 in] above crown sheet firebox)		3,700 kg	8,200 lbs
Fuel supply (coal)		3,000 kg	6,600 lbs
Number of axles per bogie		3
Number of coupled axles per bogie		3
Number of axles braked with brake shoes per bogie		2
Wheel base between both inner axles		1,000 mm	3 ft 3½ in
Wheel base between both outer axles		2,300 mm	7 ft 6½ in
Total wheelbase		3,300 mm	10 ft 10 in
Distance heart to heart pivots		9,092 mm	29 ft 10 in
Total length over buffers		18,900 mm	62 ft 1/8 in
Greatest width		2,940 mm	9 ft 7¾ in
Greatest height above rail		3,910 mm	12 ft 10 in
Diameter drive wheels		900 mm	2 ft 11½ in
Grate area		2 m2	21.5 sqft
Number of flues		164
Number of flues with superheater elements		140
Diameter of flues with superheater elements	(outer/inner)	70/64 mm	2.76/2.52 in
Diameter of flues without superheater elements	(outer/inner)	41.5/37 mm	1.63/1.46 in
Diameter of superheater flues	(outer/inner)	22/17 mm	0.87/0.67 in
Distance between tube plates		2,500 mm	8ft 2½ in
Distance between superheater flues and tube plate firebox	(top)	425 mm	16.7 in
	(bottom)	375 mm	14.8 in
Heated surface in contact with combustion products of the copper firebox		9.4 m2	101.2 sqft
Ditto flues		77.3 m2	832 sqft
Total		86.7 m2	933.2 sqft
Ditto of Schmidt's superheater with small diameter tubes		41.8 m2	449.9 sqft
Total		128.5 m2	1.383.2 qft
Ratio total heated area : grate area	128.5 : 2 =	64.25
Ratio evaporative surface : superheated area	86.7 : 41.8 =	2.07
Number of steam cylinders per bogie (with snifting valve)		2
Valve gear type		Verhoop
Cylinder position		inside and inclined
Diameter steam cylinders		360 mm	14.2 in
Stroke		360 mm	14.2 in
Average tractive effort at pm = 60% boiler pressure (appr 45-50% cut-off)		8,400 kg	18,519 lbs
Maximum tractive effort at pm = 85% boiler pressure (appr. 80% cut-off)		11,900 kg	26,235 lbs
Ratio maximum tractive effort : adhesion weight (at ½ supplies)	86.7 : 41.8 =	2.07
Smallest radius		90 m	295 ft
Top speed		50 km/h	31 mi/h

General design

Fig. 5. Pivot bearing and pivot and steam pipes

As to the general design of the locomotive it may be noted that the frame on which the boiler is placed, consists of two with stretchers interconnected "Differdinger" beams that decrease in height towards their ends. To that end wedge shaped pieces were cut out from the body, the protruding ends were bent up and electrically welded to close the cut-away. Thus the number of rivets was limited to a minimum.

Both pivot bearings, which are placed in the heart line of the bogies and in which both ball shaped pivots of the boiler cradle rest, have a replaceable copper implementation (fig. 5).

The pivot itself is secured against jumping out of the bearing with heavy lock plates. Too heavy rocking of the boiler is prevented by four spiral springs which are enclosed in pots in the boiler cradle. On the lower end they have a slide plate with which they are pressed onto a slider plate on the bogies. The springs have been mounted in the pots with a tension of 700 kg [1,543 lbs]. Such a spring is applied on either side of the pivot bearing.

The superheater of choice is of the make "Schmidt" at Kassel

and has small diameter tubes, a so called "Kleinrohrüberhitzer". The heated area could be increased by appr. 15% and the superheated area with appr. 50% in comparison to a superheater with large tubes, a so called "Großrohrüberhitzer". Accordingly the locomotive described here can bring steam on a superheated temperature in a very economical way. With the existing short distances between the halts and with shunting services this is especially advantageous because the highest superheated temperature is achieved after only a short riding distance.

Deviating from the conventional design following a proposal of the "Rijkstoezicht op de Spoorwegen"[1] the water tanks are not located on top of the bogies but slung under the footplate on the outside of the bogie frames[2] and the inside cylinders and valve gear are located in a with dustcovers encased space as is customary in this country for tramway locomotives that run on public roads in connection with riding stability, whirling dust and splashing water.

Water is prevented from flowing out of the four water tank openings on gradients by butterfly nuts that keep the tank lids well closed. In the tube interconnecting the water tanks of both bogies a manual cock is placed that enables cutting off the tanks of each of the bogies at will. For coal two bunkers are located immediately behind the driver's cab on the rear of the boiler cradle with an aisle in between that can be accessed from the driver's cab. By this aisle the underlying rear pivot is easily accessible and the view for the driver is improved[3].

A water tank on top of the bogie would result a dangerous unloading of the front driver by gradual depletion of feed water, to which upward thrust of the crossheads due to the inclined cylinders would have added. A tank closely located in front of the boiler would have impeded cleaning and maintenance work in the smokebox and of the inside motion. It would also have been less than desirable for the so much needed good view of the driver.

Here outspoken gratitude is due to the Inspector General of Rail and Tramways for his attention he was willing to give to the design of the offering manufacturers, originally all with the for railways customary implementation of water tanks on the bogies and moreover his willingness to allow the State Chief Mechanical Engineer D. Verhoop to take part in the negotiations with the supplier of the locomotive in order to resolve the objections against the design of this locomotive. We want to express our gratitude once more to mr. Verhoop for the implementation indicated by him and accepted by us and the manufacturer, which proved well suited for our company.

It was achieved that the load distribution over the axles remains as good as unchanged during water consumption, that the motion and the steam conduits on the bogies are easily accessible by lifting protective hatches and finally that visibility from the driver's cab onto the track is sufficient.

Notes

[1]	State Railways Authority
[2]	The original article mentions the water tanks were attached with "bokken". I have no clue what it means so I left it out.
[3]	When running in reverse

Axle load

The axle load of the locomotive as built was determined by weighing as shown in the following table:

Tabel 1a. Axle load (metric)

Tabel 1b. Axle load (imperial)

Brakes

The freight cars to be transported are mainly from the Nederlandsche Spoorwegen[4] and consequently fitted with airbrakes. The passenger cars of the Limburg Tramway Company have a vacuum brake. The "Garratt" locomotive will also be used for transportation of passenger trains. On the locomotive four types of brakes are available. Combining of these four brakes is prohibited to the driver to avoid confusion. It is especially prohibited to use the steam brake in conjunction with the air brake, because this can give rise to forces in the brake installation that have not been taken into account. The various braking appliances with their respective pressure gauges have been located in the driver's cab in an orderly fashion so the proper operation of these will not give rise to difficulties (fig. 6.)

Fig. 6. Braking diagram.

The four brakes systems are the following:

1)	Automatic "Knorr" air pressure brake of 3,5kg/cm2 [80 psi] pressure in the brake cylinder. The operation of it takes place with a 5-position brake valve. Only the locomotive and the cars fitted with air pressure brakes will be braked.
2)	Automatic "Knorr" air pressure brake as above and automatic "Hardy" vacuum brake. Operation takes place by a brake valve on the vacuum air piston with a differential valve screwed onto it. Only the locomotive and the cars fitted with vacuum brakes will be braked.
3)	Direct operating "Knorr" air pressure shunting brake of 3,5kg/cm2 [80 psi] pressure in the brake cylinder. Operated takes place with a 3-position brake valve present on either side of the driver's cab. Only the locomotive is braked. This shunting brake is mainly used on yards to prevent time loss due to refilling of the train's brake pipes and secondary reservoirs.
4)	Hand lever brake and steam brake, each alone or together. Only the locomotive is braked.

The train running downhill can be fully braked with this brake mentioned under 4 in case the airbrake would fail. With each of the four brakes 62% of the locomotive's weight at full supplies can be braked. To that end both axles with a mutual distance of 2,300 mm [7 ft 6½ in] on each bogie have brake shoes on the wheel tires. For the "Knorr" air pressure brake a brake cylinder is present on each bogie. Additionally a brake cylinder for the steam brake is present in the front bogie. This steam brake has been provided because installing a handbrake on the front bogie, that also should have been operated from the cab, would have been too problematic. The "Hardy" differential valve, that is connected between the main air brake and vacuum brake conduits, automatically sets the "Knorr" air pressure brake on the locomotive into operation if with the vacuum brake valve for whatever reason, e.g. by the emergency brake valve, the vacuum in the conduit is destroyed and the cars must be braked with the vacuum brake. If the brake is released, the differential valve returns to its original position. If exclusively air braked cars are transported the connection with the vacuum brake can be closed by a valve.

Notes

[4]	Dutch Railways

Steam, brake and water pipes

Two steam conduits run from the superheater header to a valve on either side of the smokebox. Each of these valves, to which an air suction valve is attached, serves via a live steam pipe the two cylinders of one bogie. Thus it is possible to disengage the cylinders of one bogie completely and run solely on those of the other bogie.

Both steam blast pipes of the two cylinder pairs join in the smokebox and end in a common nozzle below the chimney base. In the main steam pipes for both fresh and spent steam in total 4 ball joints, 4 ball joints with expansion coupling and 1 expansion coupling have been installed. Both main steam pipes lay on top of each other on the bogies.

They run through the pivot bearings through the vertical heart line of these. Between the two pivot bearings the main steam pipes run parallel to each other and in a straight line under the boiler. Both pipes on the bogies are connected at the pivot bearings to those under the boiler with each one ball joint, that lies only a small distance from the pivot's heart line. (Fig. 7.)

Fig. 7. Ball joint.

Due to these ball joints wear of the pivot will not negatively influence the tightness of the connections. At half-length between the cylinders and these ball-joints an additional ball joint with expansion coupling is present that allows for expansion and shrinkage of the pipes (Fig. 8).

Fig. 8. Ball joint with expansion coupling.

This way it is achieved that the position of the bogie depending on the track situation cannot exert an adverse influence on the steam pipes. Of both relatively long pipes under the boiler only the one for fresh steam needs an additional expansion coupling approximately in the middle to enable expanding and shrinking of the pipe. (Fig. 9)

Fig. 9. Expansion coupling

All joints and couplings have regular lead-graphite gaskets. All conduits as well as the boiler are insulated with crumpled "Alfol" aluminium foil[5]. The fresh steam conduits for the operation of the cylinder valves, the steam brake and the pressure gauge for the measurement of the pressure in the cylinders which are placed on the boiler cradle, are connected by flexible metal hoses to corresponding conduits on the bogies; the conduits for the air brake, sanding gear, steam heating and water have simple connectors of rubber hose. The grease conduits for the cylinders are connected by a copper pipe that is bent is a large curl. All pipes are arranged in such a fashion that the wheel sets can be removed from the bogie without detaching the conduits. By installing a small pit under the track with removable rail sections above it is possible to remove each wheelset quickly and easily.

Notes

[5]	Brunner uses the term "silver paper" which I presume to be the customary but inexact Dutch expression for aluminum foil.

Servomotor for the reverser

A servomotor, consisting of a steam cylinder[6] for saturated steam with a glycerin buffer[7] on the extended piston rod, is applied to operate both coupled mechanisms for the movement of the steam valves of both engine bogies easily en without effort (Fig. 10)

Fig. 10 The steam reverser mechanism

The steam piston is manually moved forward and backward with a lever in the driver's cab which is connected to a slide-valve on the cylinder. During the movement of the slide-valve in the position forward or backward a valve at the glycerin buffer simultaneously opens a narrow by-pass channel between both cylinder halves on opposite sides of the piston. The movement of the steam piston is transferred via the extended piston rod onto the reverse arm of the curved guide[8] of each engine bogie.

Hereby the glycerin in the buffer is forced to flow through the narrow by-pass channel from one side of the piston to the other. An indicator next to the reverser lever in the cab indicates the position of the (reverser) steam piston in the cylinder, and consequently also of the curved guide and thus the cut-off of the power cylinders in the engine bogies. By placing the reverser lever in the middle the admission of steam to cylinders is cut off. Simultaneously the narrow by-pass channel in the glycerin buffer is closed, so that the steam piston and consequently the curved guides cannot alter their position any further. This way it is possible to run with any constant cut-off.

Notes

[6]	Right on fig. 10
[7]	Left on fig.10. This cylinder is generally referred to as the Power Reverser's Locking Cylinder
[8]	Here the Joy´s valve gear equivalent is used.

Sanding equipment.

A lot of attention has been paid to the proper operation of the sanders because of location of the track in close proximity of public road over long distances, the presence of trees and gradients. Two sandboxes with short delivery pipes are located at the front and rear of each bogie so sanding in front of the bogie is possible in either running direction. The sanders are operated by compressed air. With an air valve in the driver's cab with three positions, viz. forward, closed and backward, it is possible to operate four sanders in every running direction, two in front of each bogie.

Road trials

These gave the following results:

Table 2a. Tractive effort (metric)

Table 2b. Tractive effort (imperial)

Table 3a. Efficiency (metric)

Table 3b. Efficiency (imperial)

Verdict.

The Garratt locomotive fulfills all requirements. The locomotive runs particularly quiet. The operation is easy and the view of the driver is completely sufficient even where the track runs alongside the public road. Moreover, the locomotive is a very good steamer. With the loads for the Garratt and the 0-4-0 locomotive mentioned above the Garratt had in comparison a 39% lower coal consumption.

Literature

1)	Lionel Wiener; "Les Locomotives Garratt". Bulletin de l'Association des Ingénieurs issus de l'Ecole d'Application de l'Artillerie et du Génie
2)	H. Kruse; "Die Entwicklung der Gelenklokomotive" Der Waggon und Lokomotivbau; No 19 of 20-9-'27
3)	W. Thormann; Hanomag Nachrichten, No 169/170-'27
4)	Böhmig; Henschel Hefte, No 3-1932
5)	Brochure "Beyer-Garratt" Patent Articulated Locomtives of Beyer, Peacock & Co.