Tag: General

This week we’re taking a look at the work our Test Car 2 was built for, namely the slip/brake testing of freight wagons. 

For 50 years from the late 1960s the acceptance of new or modified wagons onto British Rail included dynamic brake testing predominantly carried out using the slip/brake method. This test measures the brake stopping distance performance of the wagon independently, i.e. not coupled with other vehicles in a train. 

In order to conduct slip/brake testing a special coupling arrangement was used on Test Car 2, the design of which originated from use on North Eastern Railway J21 and J25 type steam locomotives providing banking assistance on the Darlington to Kirkby Stephen line over Stainmore Summit in the 1940s and 50s. 

In addition to the slip coupling, the brake system on Test Car 2 was modified such that a test engineer could independently operate the brakes of the wagon under test without affecting the brakes of the test coach or locomotive which remained under the control of the driver. 

A typical slip/brake test train would consist of a locomotive, Test Car 2 and the wagon under test. Class47 locomotives were preferred for the slip/brake testing, not just because they had adequate power to accelerate quickly; also, the responsiveness of the engine control system of the Sulzer locos (compared to the English Electric locos) made it easier for the driver to control the speed more accurately with the short and often light trailing load of a test train. 

The slip/brake tests were normally carried out on the Down Slow line of the West Coast Main Line between Crewe and Winsford. To ensure safe operation a ‘T3’ possession of the Down Slow line was applied by the Crewe Coal Yard signalman, making sure it was blocked to all traffic and protected by stop boards and detonators at each end of the possession section.  

This section of line was particularly suited to the slip/brake testing because the test section was level, and the four-track formation allowed normal traffic to continue on the other three lines whilst testing was in progress. 

It was not permitted to carry out slip/brake testing during hours of darkness, thick fog or falling snow and at least 1mile clear visibility was needed before testing could commence; this was because the test engineer had to be able to clearly keep the test vehicle in sight at all times when the vehicle was detached from the test car. 

A slip/brake acceptance tests of a wagon would normally be carried out over two days, one for each load condition, so one day for empty and one day for loaded wagon. 

Each day would start with test engineers joining the test train at the Derby RTC, a loco would arrive from Derby 4-shed and would transit to Crewe. The train would pause in the station to pick up a Traction Inspector, (and some sandwiches) then continue onto the Down Slow line at Crewe Coal Yard. The T3 possession was then set-up to protect the line, the train brake systems were configured for test and static test checks for correct operation were carried out. These static checks included measurement of brake cylinder application timings and pressures on the wagon under test, and a continuity brake test on the locomotive and test car brakes. 

Heavy duty instrument cables were attached from the test car, along the outside of the locomotive and into the leading cab (normally through the drivers’ cab-side window) and connected to twin intercom speaker/microphone outstations. The locomotive was always manned by a driver and a traction inspector for slip/brake testing; this allowed the test engineer to communicate using the intercom directly with the traction inspector in the cab so as not to distract the driver from his duties. 

Once the intercom was tested and the static brake tests completed to the satisfaction of the test engineer, the slip coupling was fitted between the test car and the wagon, and testing could commence. 

A slip/brake test is described in stages as shown in the diagrams below. 

The test engineer calculated the wagon brake stopping distance for each slip/brake test run, taking the total distance from the point at which the brakes were applied on the wagon until the locomotive and test coach had stopped, then subtracting the distance the locomotive and test coach had to reverse back to collect the wagon. The results were plotted on a speed/distance graph. 

The stopping distance limit in 1987 for a wagon running at 75 mile/h was 951metres, the graph below shows test results just failing to meet this, therefore this wagon would have been subject to modification to the brake system before a retest. 

A deceleration meter fitted on the headstock of the wagon containing a calibrated accelerometer and a low pass filtered output onto a strip paper chart provided an accurate measure and characteristic of deceleration rate of the wagon throughout each slip/brake test. 

Tests were always carried out at varying speeds from 30 mile/h up to the maximum operating speed of the vehicle under test. On average 15 slip/brake test runs could be completed during a day’s testing, however the achievable number of tests varied depending on how slick the team on board was working, the type of locomotive, the performance of the wagon under test, and more often than not, the weather. 

After testing was completed the slip coupling was removed and a standard screw coupling re-attached, the brake system was configured back in the normal manner and the statutory brake continuity test completed before the train was hauled out of the test site. The train would then proceed up to Winsford for a loco run-round before returning via Crewe to the RTC at Derby. 

In addition to wagons, on-track plant and coaching stock were occasionally slip/brake tested, for example this Cowans Sheldon 75t breakdown crane needed testing after it was modified by fitting air brakes in 1987.  

Due to the fall in wagons requiring testing and UK network access constraints, slip/brake testing on the UK network finished by 2010. Computer modelling and dynamometers offer alternatives to testing now days although this type of testing does continue in mainland Europe and has also been done on private lines. An example were the tests done some years ago at the GCR, albeit without the need for a test coach since the computer took over. The link shows a Youtube video of a GCR slip/brake test run using D123 in July 2009.

Once the GCR is up and running again, keep a look out for events at Quorn when we hope to have Test Car 2 open to visitors again with displays and more information about its history and slip/brake testing.  

For those with an appetite for more detail, the full story of Test Car 2’s work during the 1980s and 90s, along with accounts of why and how wagons were tested for acceptance onto British Rail, can be found in Dave Bower’s Rail Vehicle Testing book. ISBN 9781999935603 https://www.bowerbooks.co.uk/ 

Lastly, we await news from the GCR following the government announcement tomorrow whether we can re-commence working on the fleet again, continuing we’d left off on the Yellow Coach and 2 tank wagons. Either way We’ll be back with another feature, or hopefully an update. See you then.

This week’s feature again starts with a small update: Matt returned to Mountsorrel to complete their LMS 12T van, mainly the east side door and the solebar ‘D’ Plates which completed the van.

The van was drawn outside by Mountsorrel’s resident Ruston, so the livery could be seen outside for the first time.

I have been continuing to make progress on the Slip Lamp for Test Car 2. All components have now arrived, so I can now focus on final mountings for all components and then wiring. As Matt said last week, we will have this on show as and when we can open the Test Car to the public again.

This week’s feature is a bit of a sideways step from the wagons, but is all about the road/site vehicles that support our endeavours restoring our wagons. The first to mention is our one-ton site dumper, Danny.

Not a lot is known for Danny’s history, but it was built by Winget around 1976. The dumper was registered in 1976 with the registration number PUT 666R. Danny is a Winget 3SE, and was in use by a local scout campsite before Nick became the owner. The powerplant is a Petter PH1, producing an enormous 9hp running to the front axle through a 3 speed manual transmission, a layout in common with many of the other site dumpers of the period. We use Danny for trumdling items around Quorn Yard and for the skip run when required. Danny can also pull a fleet of trailers we have, which added to Danny’s carrying ability.

We have begun to do some work on Danny, starting with having the steering box rebuilt. With the rebuilt box Danny was properly mobile again, so it was decided to paint Danny into a scheme representative of its current location. This started last year, but got postponed due to the decreasing temperatures.

The next vehicle is the Volvo BM L70 Loading Shovel, bought by the railway for the P’Way department to replace an even older Volvo Loading Shovel (still very muich missed from my point of view). The P’Way department now use a Telehandler, so we have sole use of the Volvo which we use to remove vacuum cylinders and generally lift and shift items around the yard.

There is a little work outstanding on the Volvo, mainly on the exhaust system. A new silencer is required and the relvant pipes to connect it to the turbo outlet. If anyone knows where we might get a suitable exhaust silencer for this, please do get in touch! Once the exhaust is done, we’d like to give it a spruce up.

Lastly, the one vehicle I would be remiss not to mention would be Nick’s daily driver, the humble Transit Van. Without the van, we’d not be able to move anything between the sites without the relative ease that we have or have the ability to collect wood from timber merchants and keep it dry or any other tasks like that. A very useful vehicle indeed.

When we are able to return to the railway, we will look to progress these vehicles alongside the rest of the wagon fleet.

Our feature image above shows the beginnings of our tanker train with 1408 joining the rake this week after being shunted from Rothley by the Operations department. Before I get into the bulk of this feature, in fact if we are honest this is an update, Monday saw the arrival of 2 vehicles from the Llangollen Railway.
Ferry tank B749677 Diagram 1/305 built to Lot 2429 in 1952 at Ashford. Once complete this will of course join the fledgling tanker train, as it stands we are considering restoring it into Traffic Services Ltd Black livery as number 500817
The other vehicle a chassis, this being former Shell Mex and BP Ltd tank 6463 and will receive a van body but I’ll leave it at that for the moment.

Images courtesy of Andy Maxwell

Next I managed to get my brushes out. The Rothley and Mountsorrel Heritage Centre have been pressing forward with the restoration of an LMS 12T van. They have been following Government guidelines that class volunteers of charitable organisations as essential workers, so Michelle and I were allowed on site to progress the vehicle.

Images courtesy of Steve Cramp

Working in isolation, with other volunteers on site restricted entry to the workshop I gradually applied the livery. This being a slightly earlier style than what would have been applied to the vehicle but this fulfils the owners brief and adds further interest to the centres fleet.

One side complete, all but the door on the other and the sole bar plates backed.
It was nice to get out at a weekend especially for my wife who has been furloughed since September and like most has been struggling at home alone whilst I’m at work.

Not just myself working however, Ross has been looking into the Test Cars slip lamp, manufacturing new internal electronics replacing the life expired originals. The lamp displays flashing white lamps when the slip test vehicle is moving and a steady red when stopped, there is also a test button and for our purposes a demonstration mode to enhance our tours of the Test Car when we are allowed to open again.

So now on to the feature.

Sometimes we are asked “Why do you spend almost all of your spare time restoring wagons?” Why indeed? Although the following was written sometime ago for an unpublished article, its intent remains.

Visiting the GCR’s 2018 Model Rail Event from Surry, Mr Robert Holah noticed in the lie-by siding at Quorn our London Midland Scottish Railway (LMSR) Brakevan M730562. 

What brought this particular vehicle to his attention was its similarity to one pictured in an image of his father.

Allbert Edward Holah was a Goods Guard, initially with the LMSR and then British Railways London Midland Region upon nationalisation of the railways in 1948.  He was based at Harrow and Wealdstone station.  In fact he was at the Station on the 8^th October 1952.  It was a foggy morning and the 07:31 Tring – Euston local train was stood in Platform 4. At 08:19 this train was struck by the Southbound Perth – Euston Express, the resulting wreckage was then hit by the Northbound Euston – Liverpool Express on the adjacent line.  112 were killed and 340 injured and it remains the worse peace time rail accident in the UK and basically resulted in the nationwide introduction of the Automatic Warning System (AWS).  The incident affected Albert quite deeply.

Albert later became an instructor and as such trained a number of immigrants from the Caribbean, what has now become known as the Windrush Generation,  he opened his home to a young Caribbean Gentlemen during Christmas who’s family remained at home in Jamaica. Robert remembers this well and Mrs Holah’s annoyance of not being informed of his farthers guest and being unable to fully prepare.

Unfortunately Albert’s colleagues were not as charitable and saw the immigrants as a threat, taking their jobs.  As a punishment the union forced Albert to Coventry and ordered his colleagues not to communicate with him.  This of cause affected Albert even further and in 1959, 18 Months after being moved, he suffered a heart attack and died.  Robert at the age of 12 was left with an image and memories. 

After an email to the GCR and being forwarded on to us at “Quorn Wagon and Wagon”. Robert came and visited on the 1^st September 2018. We had spent a number of weeks repairing and carrying out a full interior and exterior repaint to M730562. We also added extra items that Roberts farther would have instantly remembered.  Guards Bag, Tea Can, Paperwork, Newspaper, Railway Observer, Lamps, Shunters pole, Brake Stick along with other items.  We also lent Robert a BR uniform identical to his fathers including the Midland Region Staff association tie he is wearing in the photograph.  This allowed Robert to recreate the image of his farther.  The artifacts in the vehicle brought back a number of further memories for Robert, playing with his father’s handlamp rotating the handle between Red, Green and Clear. His father sat fettling a wooden implement one end square the other round.  With that description we handed Robert a Brake Stick and demonstrated its use as well as the use of a Shunters Pole.

We continue to extend our thanks to Robert for coming down and sharing his memories. We know he enjoyed his visit and will be coming back to see us soon. So why do we restore Goods Wagons?  A tangible link to the past, maybe not directly for us but certainly for others, as was the case for Robert. It may never be proven but we like to think that Albert may have worked M730562 at least once in his career.
Goods vehicles are an important part of railway history it’s the reason the railways were built.  To recreate the sights and sounds of a bygone railway then they are an essential part of the scene and a draw for our visitors, not just the ones we care for but all those none passenger vehicles at all Heritage Railways across the country.

That is why we restore wagons.

Without a doubt our vehicles are most visible when they are either static in sidings or operating at Galas or during Photocharters.

But recreating bygone sites and sounds is not the sole purpose of our fleet.
The first group of vehicles continuing to do the work they were built for are the Ballast hoppers. Centre line Catfish and Sholder and Centre line Dogfish. There purpose to transport and dispense ballast were required.

The most notable case being the recent laying of the Mountsorrel branch, after the hard work by the volunteers to remove the vegetation, prepare the ground, lay the first layers of ballast and of course the track, the ballast wagons were brought into stabilise the permanent way.

We extend our thanks to Steve Cramp and the volunteers of the Mountsorrel Railway for providing these images as well as capturing the videos below which also include a Ballast Plough in operation, although not a member of our fleet it is also vital to the work being carried out.

Above I mentioned the rail being laid but how did this get moved to site? Well that’s were our next group of vehicles comes in to it, the flats, as the rail head moved forward, wagons carrying rail would drop it of, this would then be moved by hand a length at a time and the Mountsorrels Wickham trolley would follow keeping the rail no more that a length behind the rail head. Then another bulk load would be dropped off and the process continue.

Keeping with the flats we look at bridge repairs, the most recent replacement of Bridge 341 and repairs to Bridge 350. With flats being used to carry brick work for the bridge in the case of 341 and the floating pontoons for Bridge 350.

As well as Bridges, Canopies also require flat wagons. Specifically the repairs to Loughborough’s Canopy. The Tank flat was used to carry the main canopy structures from and to the work site as well as the single bolster used not only to remove materials but as a means to reduce the amount of scaffolding required to conduct the task.

With the wheel base of our examples reducing we turn to the ballast opens namely the Grampus and Rudd wagons. These are basically the railways general utility vehicles used to fetch and carry anything and everything. Ranging from ash to sleepers, spoil to vegetation.

Another popular vehicle is the Caledonian Weltrol, at one point labelled the single most active vehicle on the railway. With a long spell of use with the S&T department running out cable the full length of the railway. At this present moment it stands in Quorn yard with the tender tank from a certain GWR Castle class locomotive upon it, stored awaiting fitment to its chassis.

Staying with locomotives, both of the road and rail variety we have two vehicles used to store water. 1408 being the primary water source for filling locomotives at Swithland and A4513 having been used for traction engines at Quorn.

The list of work carried out by these vehicles can continue and this can of course include Film and TV work which would create its own long list of appearances.
But I hope this gives a little insight in to those aging departmental vehicles that don’t really appear to do anything but occupy sidings. As we get closer to the completion of the gap these wagons will once again be called upon to carry out there vital work and once that and any possible doubling of the track to Leicester is carried out they will still be ready for the next set of bridge repairs or bank slip or major civil project the GCR wish to use them for.

But wait I have forgotten 4 vital vehicles in our fleet, every time they move they are conducting the work they were built for and appear in a few of our images. They are used for their original purpose even when part of a demonstration train. I am talking none other than the focus of our last feature.

We do have plans to work on our departmental fleet and return them to their Black and Straw lettered livery but after we have completed the more vulnerable freight vehicles, They will however continue there work and be available for any engineering needs, after all there is a sense of authenticity in a rake of rusty and battered wagons going about there business.

We also wish to thank the GCR for supplying images for this feature and credit to those photographers who captured our vehicles at work.
David Howdle for the vehicles atop bridge 350 unloading pontoons
Graham Wignall for Rails being unloaded behind 47406 & Track ballasting from a Grampus at Swithland Sidings
Tony Sparks for Loughborough Canopy work images.

Feature image courtesy of Clive Hanley
Over the past 4 years we have been steadily increase our van train. We have a number of possible opportunities to reach our target of 20. Although the overall plan is a fixed rake of 17 with 3 spare to operate within the Mixed freight or to bolster the main rake during charters. The total is currently 15 so we are 5 short. Although this can be fuddled with the use of the Fish Van and Container carrying vehicles. The past 2 years have seen us refresh a number of other “mixed” vehicles but the latest focus has been the tanks.

The plans for a tank train first saw its inception with the Swithland wagon group who made a great effort with our first 2 contenders. Privately owned 6071, built by Charles Roberts in 1949 for Shell Mex & BP Ltd to transport fuel oil and later used by BR as a Departmental tank, as well as our very own 6581 another Shell Mex & BP Ltd tank although built by Fairfield Bridge & Engineering in 1948 and used for Lubricating Oil and again latterly used as a Departmental tank, both saw there first outing in 2018.

Next to see the light of day was 4513 another Shell Mex & BP Ltd tank used for Petroleum spirit built by Hurst Nelson in 1941, this came in to our care towards the end of 2019 and received a top half refresh last year, sparking our current desires to progress with a tank wagon train.

Our next vehicle has been the focus of a number of our recent updates but we shall take this opportunity to discuss in a little more depth its unique suspension, that is unique to the GCR, quit common on the national network.

So 1408 a China Clay Slurry tank built by Charles Roberts in 1965 had a fair amount of attention which included lifting the vehicle for suspension inspection.

If the damping in the suspension of a wagon were to be too low this could cause the vehicle to bounce uncontrollably leading to a derailment; likewise, if the damping level is too high then the suspension will not move freely enough to accommodate any undulations or twists in the track which again could also lead to a derailment, particularly at low speeds. 

When 1408 was new the Gloucester pedestal suspension design would have been tested to ensure the level of spring stiffness and damping present would be suitable to allow the wagon to accommodate undulations or track twists. The test called a torsional stiffness test (or Delta Q/Q) was carried out on a calibrated weighbridge, where the wagon is subjected to a defined twist whilst measuring each individual wheel load. The amount of load on each wheel must remain within 60% of the average wheel load to pass the test. 

The first graph below shows the test results from a torsional stiffness test where the wheel load remains within the limit when the wagon is twisted to 1 in 150. The thickness of the band of results for each wheel gives an indication of the level of friction damping in the suspension. 

Whereas this second graph shows that the wheel load on wheel 2 drops below the 60% offloading limit; in this case the combination of the stiffness in the suspension or the wagon underframe and the level of friction damping is too great therefore a change to the design would have been necessary. 

Once a wagon has passed its test then a maintenance plan must be implemented in order to maintain its compliance. In the case of 1408, we must ensure that the friction dampers continue to operate as they did when the suspension type was initially tested, therefore we undertook checks of the condition of the friction surfaces on the axlebox and plunger, and ensuring the freedom of operation of the friction wedge and plunger. 

In order to do this we lifted the wagon using the vehicle lifting jacks at Rothley until all the weight was released from the suspension and the condition of the friction surfaces could be checked. Whilst the wagon was lifted we could also check the springs for any fractures. 

When lowering the wagon back onto its wheelsets the operation of each friction wedge and plunger was noted, the lift and lower process was repeated a few times to check there was no sticking of the components. 

After lowering the wagon back onto its wheelsets a check of the buffer heights was made to ensure it had lowered fully and evenly, then the wagon was shunted around the yard a few times to settle the suspension before the buffer heights were checked again and confirmed to be within tolerance. 

Our checks on 1408 confirmed all was in order and that the suspension is operating as it should, therefore ensuring wheel unloading is maintained within the limit levels. 
The diagrams and reference material are taken from Dave Bower’s book Rail Vehicle Testing 

As the second update of this year confirms our focus is now on 3436 a 22T B Type Esso tank built by Charles Roberts in 1958. This will be returning to its as built Esso condition and the templates are already ready. We are just waiting for the opportunity to return and complete it.

Following 3436 will be DB998926, this is a BR 14T departmental creosote tank built by Charles Roberts in 1959. This 3rd lockdown has already been a help, as my research has successfully identified its original region and depot allocation. This being the North Eastern regions West Hartlepool Sleeper Depot. This tank will receive its full departmental livery of Black with straw lettering including this original allocation.

That gives us a possible train made up of 6 tanks, but wait there is one more. Located at the Mountsorrel Heritage Centre is Tar Tank 339, a National Coal Board tank built by the Cambrian Wagon Works in 1940. With the permission of the centre I’m sure this vehicle could run with the 6 to create a train of 7 vehicles.

Unfortunately that is as far as we can go but who knows what the future could bring. There is however, Covid not withstanding, the opportunity to see these tanks together. This has been organised by Timeline events and will be hauled by Standard Class 5 Locomotive 73156. Currently set to be Monday 19th April and Tuesday 20th April, the links will take you to further information, of course this may be subject to change.

Image courtesy of Clive Hanley
So hopefully that gives a little insight to our current focus and aims. Next week we have yet to decide but it will likely be the continuation of our vehicle profile series started during the first lockdown.

Early wagon brakes were operated by a simple lever and acted on only a single wheel, however from the 1880s the handbrake design by Morton that we see on many of our wagons was developed.

The brake lever extended upwards from a centrally mounted ‘V hanger’ and brake blocks were pressed against the wheels by push-rods which passed through metal supporting loops called ‘brake hangers’. The long brake lever allowed the shunter to exert a considerable force on the brakes. Levers generally extended up towards the right hand end of the body and the handle on the end of the brake lever was usually painted white to make it more visible.

Whilst early wagons had single push blocks on one side of the wagon only, as the weight of wagons and their loads increased so did the amount of braking effort required. Greater braking effort came from using brake blocks on both sides of the wagon and later by using clasp brakes which have two blocks per wheel.

Various designs evolved to transmit and multiply the applied lever effort to the brake blocks to ensure that sufficient brake force could be easily applied to hold a loaded wagon on a gradient. A cam or slotted link arrangement is used so that the handbrake on either side of the wagon operates the brakes on both sides via the transverse shaft.

Handbrakes can also be used during the operation of partially fitted or unfitted freight trains which have no means for the driver to brake the unfitted wagons when he needed to slow down or stop the train. The guard ‘Pins Down’ the handbrakes at ‘Stop and pin down wagon brakes’ locations (usually prior to a severe downhill section of track and known by train crew as part of their route knowledge) so that the handbrakes help ensure that the driver retains control of the train on the downhill section. The train then stops again at the bottom of the incline to allow the guard to ‘take up’ the handbrakes (release them).

The effectiveness of the handbrake on a new design of railway vehicle is established by conducting a static test, whereby the force needed to move a vehicle along the rails, with its handbrake applied, is measured. This resulting force is used to determine the gradient on which the handbrake will hold the vehicle.

In order to move the test vehicle along the rails, a hydraulic ram fitted with a calibrated ‘Load Cell’ is installed between the drawgear of the vehicle under test and an anchor vehicle on the same line. The anchor vehicle was parked with its brakes fully applied and chocks placed tightly under each wheel.

A test is not valid if the wheels slide along the rails, therefore it is important to carry out a test within a workshop, where the rails are clean, dry and preferably level. To ensure a consistent and representative application of the handbrake lever, weights are attached the lever that are equivalent to the standard level of effort that could normally be applied at the lever end by the average person weighing about 60kg applying the handbrake. The test is always repeated to assess the performance of the handbrake when applied from both sides of the vehicle.

The acceptability of the performance of a parking brake was assessed by establishing the gradient on which the vehicle under test could be held without rolling away. The British Railways standard requirement for the design of freight wagon handbrakes is such that each wagon must be able to hold its fully laden weight stationary on a gradient of 1 in 40.

The hydraulic ram is operated either by a hand pump or by an electrically powered hydraulic pump in order to haul the vehicle under test for a distance of between 8and10inches along the rails. The measurements taken from the load cell of the peak value of resisting force are used to calculate the equivalent holding gradient result as follows:-

Where:-       

After each test is completed it is necessary to return the vehicle back to its original position ready to start the next test.

Many locomotives, coaching stock vehicles and newer designs of wagons are fitted with a handwheel & screw type method of applying the handbrake.

The principle and method of testing is very similar however instead of using weights applied to the handbrake lever, a specified level of torque is used when applying the handwheel. This is calculated and applied with a calibrated torque wrench based on the diameter of the handwheel and the standard level of effort of 500Newtons applied at the handwheel rim.

An example of the table of results produced during a handbrake test on a wagon fitted with a handwheel type handbrake.

In general the handbrakes fitted to freight wagons are more than sufficient to hold a loaded wagon on a steep gradient when applied fully; therefore when they are applied to an empty wagon their effectiveness is significantly increased. As such, if an empty wagon is moved with its handbrake ‘ON’ then the effectiveness of the brake will cause the wheels to lock and slide; this can very quickly cause significant damage to the wheelsets in the form of wheel-flats and cavities that are costly to rectify.

This is an example of wheel tread damage caused by operating a vehicle with a handbrake on.