Industrial locomotive and railway siding safety must be registered,licensed to the National Railway Safety Regulator (RSR) and conform to SANS 3000.
Private sidings are served by main lines, and rolling stock is delivered to the siding by the national operator, writes Rudy Maritz.
After the national operator detaches rolling stock, they fit and lock a ‘derail’ to one of the rails. A derail, sometimes erroneously named a ‘derailer’, is a safety device to derail rail cars and prevent rolling stock from unintentionally fouling the main line.
The position where the derail should be fitted is at the start of the private siding. The private operator then uses its own locomotive to move the rolling stock on the siding.
According to SANS 3000, a Railway Safety Management System is “a dynamic management-driven process that requires commitment and understanding at all levels within an organization, and documentary evidence of the elements of the system at the relevant levels within the organisation”.
The risk-driven process focuses on preventing:
• level crossing vehicle collisions
• pedestrian impacts
• roll-back onto the main line.
Derailment is the partly or total dislodging of a railcar from the track and is mostly caused by track wear over long periods.
Train wheels are built in such a fashion that the surface of the wheel on the track tapers outward, to accommodate bends and turns. As a train goes around a right hand curve, having two wheels on a solid steel axle, the wheels move to the left.
The taper of the left side wheel increases the circumference, while the right side wheel does the opposite. Both wheels have flange-like edges that prevent them from slipping over the top of the rail (head).
Should the gauge of the track (distance between the two rails) be greater than the axle width, the inner wheel will slip off and could result in the derailment of the car, or an entire train.
Usually, tracks in curves are fitted with re-railers (short lengths of rail mounted inside the main tracks) to force the derailed wheel back on the track. Re-railers are also commonly found inside switches or points, (where one track splits into two tracks).
Another cause of derailment is the displacement of ballast, which is the stone packed between the sleepers. Dislodgement of ballast is also more common at steep inclines, as the traction of the locomotives put severe lateral strain on the rails, pushing an entire length of track as far as 50cm outward over a period of a year.
Soil erosion beneath the ballast is also another cause of displacement. When the ballast is displaced, there is insufficient support for the sleepers, which due to the weight of the train, could result in the rails being “clipped” off the sleepers as the train passes a weak point. This in turn will increase the track width due to pressure.
The SANS standard includes requirements for track maintenance and inspection as well locomotive operator competency and training of technical & inspection personnel. It also provides for the design and maintenance of signalling and switching controls and most importantly, the prevention of accidents at level crossings and the control of “unmanned” crossings.
Depending on the track loading, the inspection of the entire track should be at least once per month for two or more passes per week. A pass is the movement of rail cars at any given point.
Mainline tracks, commonly operated by PRASA (Spoornet) need to be inspected weekly.
Check track gauge
Track gauge is the distance between the centre of the left rail head and the right rail head. The railways of South Africa and many other African countries, including Angola, Botswana, Congo, Ghana, Mozambique, Namibia, Nigeria, Sudan, Zambia and Zimbabwe, use 1.067mm gauge, sometimes referred to as Cape gauge.
Kenya, Uganda and others use 1,000 mm gauge lines. In Tanzania former East African Railways lines are meter gauge while the TAZARA line is 1.067 mm. The international standard gauge is 1435mm.
During inspection of the track, it is important to ensure the gauge remains within allowed tolerances over the entire track distance. This means a representative sample of measurements need to be taken over the entire distance to identify possible areas of track wear or displacement.
However, it is imperative to note that the gauge must widen in a curve within minimum radius. Freight cars are not articulated and cannot turn the wheels in the curve like a truck would. It will remain in a straight line despite the track turning.
By widening the gauge, the wheels will not climb over the rails. This is not required for curves longer than 30m and would commonly only apply to mining operations with narrow gauge rails of 600mm or less.
Check track head condition
The track head is the top of the rail on which the wheels run. Heads should be of consistent shape and inspected at regular intervals. The friction of the wheels causes the head to wear thin over long periods, and more over, in curves, the inner edge of the head become deformed.
Deformed heads may result in flange climbing where the wheel climbs up the head and over it), resulting in derailment.
Check track web
The web is the flat metal part between the head and the plate. This part takes the entire load and may start to deform and bend if not maintained regularly.
Check track feet
The foot of the rail is that part placed on the sleepers. Track feet need to be inspected for displacement. In older sidings, with wooden sleepers, it is important to check the nails holding them down.
The condition of sleepers need to be monitored for cracks. Modern rail tracks, with concrete sleepers are tied down with spring steel ties called pandrol ties and are less prone to displacement and fatigue.
Duper-elevation or cant is the cross level angle of track on a curve, which is used to compensate for lateral forces generated by the train as it passes through the curve. In effect, the sleepers are laid at an angle so that the outer rail on the curve is at a higher level than the inner rail.
Although not commonly found at private sidings, it is important to ensure that the cant is within specification for the curve radius.
Check fishplates and bolts
Lengths of rail are connected with metal plates called fishplates. Two plates are fitted on both sides of the rail ends and bolted into position through the web. It is important to ensure the bolts are always on the field side of the rail to prevent damage to the wheel flanges.
The space between the two rails are the “gauge side”. In some cases section of rail are welded together. During inspection of the track it is of vital importance to inspect these connections for wear or shearing as it could cause the rail to split if it fractures.
The gap between two rails should also be checked. IF the gap is too great it causes wheel damage and excessive noise during shunting. If the gap is too narrow, it reduces the allowance for expansion/contraction of the rails and puts undue strain on the connecting bolts.
Check switches (points or turnouts)
The regular inspection of turnouts are crucial. A turnout comprises two weak points. The first is the heel or knuckle blocks and the second is the connecting rod. The most common switched are of a flexible rail type. This means the rail actually bends open and close.
The other type is the free heel switch, which is pushed open by the leading wheel of the train. The latter however only works in one direction. The connecting rod is a metal bar that is attached to both switch rails (blades).
It moves both rails to the open or close position. If the connecting rod fails, only one rail is moved which may cause severe damage to the track, the wheels and may even cause derailment.
It is also important to regularly check the counter-weight of the switch lever. The lever has a weighted flip lock which will keep it open or closed despite the pressure exerted by the wheels when passing through the points.
If the switch lever is worn out, the leading wheels of the train may inadvertently switch the points on its own causing the trailing wheels to derail. Generally switch blades should be longer than the maximum wheel base of the freight cars.
There are other areas such as level crossings, where only the rail heads and part of the webs are visible and inspection at these sections need special attention. It is best advisable to consult rail way engineers for these types of inspections.
Another problem with rail way inspection is vegetation over growth and it is thus important to keep weeds and vegetation at bay.
Critical components on locos and rolling stock
In South Africa the majority of rolling stock (freight cars) are owned by TFR (Transnet Freight Rail formerly Spoornet), while some larger companies own their own locomotives. However, while these assets are in private care, it is part of your responsibility to ensure their continued safe use.
Most locos are either diesel or diesel-electric powered and privately owned units have either a 0-2-0 or 4-0-4 wheel arrangement. Loco wheels are to be inspected prior to use to ensure the wheel surface is within specification.
One of the key safety features of a locomotive is the commonly known “dead man brake”. On older loco’s this was a lever that would engage the braking system whenever the lever is released. Modern day loco’s have an audible alarm that reminds the operator to push a button to prevent the brake activating.
Whichever is fitted to your loco should be inspected and ensure it is in working condition. A runaway loco is the last thing you need on your siding when the operator is incapacitated.
Sample checklistA pre-departure inspection of locomotive(s) should be performed by the loco operator or other qualified person for the following:
(a) brake test including the operation of the safety control system (dead-man brake)
(b) hand brake
(c) headlights and ditch lights
(d) trucks and running gear
(e) any other apparent safety hazard likely to cause an accident or casualty.
Diesel-electric loco operators should inspect the loco daily before startup;
• Electrical Control Equipment Check
• Electrical Rotating Machine Examine
• Straight air brake check
• Slack adjuster check
• Brake gear & brake blocks visual check
• Air & Vacuum hosepipe dummy coupling check
• Compressor oil level check
• Exhauster oil level check (No. 1 end ex.)*
• Coolant Level
• Power Unit Oil Level
• Triple Pump – Hand rotation test.
• General examination of body, bogies & under frame
• Doors & hatches security check
• Marker/headcode external glass cleaning
• Buffer visual check
• Wheels & tyres visual check (some steel wheels have a rubber compound for grip)
• Brake block hanger pins examination
• Portable fire extinguisher check.
Monthly maintenance checks should include:
• Handbrake operational check
• Slack adjuster visual check
• Brake gear & brake blocks visual check
• Air & vacuum hosepipe dummy coupling check
• General examination of body, bogies & under
• Doors, roof hatches, battery boxes & covers
• security check
• Wheels & tyres examination
• Bogie brake hanger pins examination
• Bogie brake hanger slides examination
• Bogie fractures examination
• Portable fire extinguisher cleaning
• Air & vacuum brake test
• Straight air brake test
• Drivers safety device check
• Speed Switch check
• Air brake pipe pressure check
• Drivers auto brake valve overcharge timing test
• Marker/headcode glass external cleaning
• Windscreen external cleaning
• Windscreen washer bottles refilling
• Windscreen wiper check
• Warning flashes check
• High visibility panel cleaning.
Loco operator competency
It is important to ensure that operators are qualified in terms of the Principles of Safe Movement on Rail (POSMOR) principles under Unit Standard 61849 as a minimum.
Control level crossings and pedestrians
It is compulsory to ensure the safety at level crossings to prevent vehicular traffic being affected by trains. To this extent, a proper Standard Operating Procedure should be developed for:
1. Crossing a road and the use of flagmen,
2. Splitting of trains on a level crossing to allow passage,
3. Shunting operations from the trailing end of a train, (where the front cannot be seen)
4. Communication between operator and signalman.
5. Security arrangements for protection of the public.
Railway siding safety is a specialist engineering field, and it should be noted that this information is merely a guideline. To gain a better understanding of a RSMS, please consult the Railway Safety Regulator and SANS 3000. Permit applications will depend on the type of operation.
• Rudy Maritz is chairperson of the consulting body NIOCCSA. He writes in his private capacity as a consultant.