Erasmus studend: Dihoru Ioana Izabela

Railroad Maintenance

Maintenance has long been an important part of railroading although not

always mechanized like it is today. An essential ingredient in the successful
running of a railway is a well maintained system. Train maintenance is very
important.

Railways are made up of complex mechanical and electrical systems and

there are hundreds of thousands of moving parts. If a railway service is to be
reliable and safe, the equipment must be kept in good working order and regular
maintenance is the essential ingredient to achieve this. A railway will not survive
for long as a viable operation if it is allowed to deteriorate and become unsafe
because of lack of maintenance. Although maintenance is expensive, it will
become more expensive to replace the failing equipment early in its life because
maintenance has been neglected.

Rolling stock is the most maintenance intensive part of the railway system
and is the most vulnerable if maintenance is neglected. A stalled train will block a
railway immediately and will reduce a timetable on an intensively used system to
an unmanageable shambles for the remainder of the day. Reliability is the key to
successful railway operation and maintenance should be the number one priority to
ensure safety and reliability is on-going.

A useful maintenance cost profile is shown in

Figure 1, demonstrating that in a life cycle of a high
speed train maintenance represents 30% of the life
costs. This is broadly close to other types of trains. A
paper "Lean Rolling Stock Maintenance How to
improve efficiency of rolling stock maintenance
operations” by Oliver Wyman offers some useful
pointers on rolling stock manitnenance.
 Originally seen as a necessary evil and now looked upon as a way to
improve the business process, maintenance as a subject has developed
tremendously during the last decades. Maintenance theory is a multidisciplinary
subject. It spans from technical details to organizational methods and human
behavior. Requirements on safety, functionality, reliability and cost effectiveness
of complex systems are continuously growing as the use of them in industry, as
well as the service sectors and everyday life, is in constant expansion.
Maintenance can compensate for system degradation caused by operational
environment and usage.

Factors can affect the downtime to a greater extent. Fault reports, fault
detection, getting the right documentation, planning of the repair, requisition of
spare parts, - 18 - information retrieval, testing and start up time for process will all
affect the total downtime. These factors are defined in the maintenance standards
as the combination of all technical and administrative actions, including
supervision actions, intended to retain an item in, or restore it to, a state in which it
can perform a required function.

Figure 2. The relations between maintenance, operation and modification

The performance of the system is dependent on the stated design

parameters, which are based on the required functions. Stakeholders have
performance requirement on the system. The required functions are set in the initial
design state to achieve the performance requirements set for the operation of the
item/system, which is the combination of all technical and administrative actions
intended to enable an item to perform a required function, recognizing necessary
adaptation to changes in external conditions.

In the railway industry the maintenance intervals are often traditionally time- or
mileage-based, and these intervals are often based on earlier experience or on the
supplier’s specification. This method of maintenance can be further improved, if
the variations in wear can be more accurately anticipated, see Figure 3.

Figure 3. Average wear and the spread for the condition of a component

The interval-based concept often has the effect that the maintenance
intervals are set at the minimum level of the component’s average life length. But
even so, it is possible to have components that deteriorate faster than anticipated
due to, for example, some failure caused by an external factor. Maintenance based
on actual condition would be more economical. Condition monitoring is also a
powerful tool for detecting failures and unpredicted deterioration in the condition
of components. This can increase both the safety and availability of the system and
also optimize the use of components, see Figure 4.
 Figure 4. The use of condition monitoring to find the best point for restoring/replacing the
component instead of using predetermined intervals.

To achieve the goal of bringing the railway industry from

time/mileagebased maintenance to more condition-based maintenance, there have
to be ways to monitor the condition and thereby be able to predict the remaining
life length of the component.

Condition monitoring is a tool for the maintenance management and

function as input to the decision support. The condition monitoring infor the by ree
main areas, see Figure 48. mation is combined with information about the
operation to plan maintenance activities in an effective way to achieve increased
equipment life, uptime and decrease costs to reach a better business result. The
maintenance management decisions can be seen as determined by tree main areas:
 Connected to these areas are specific factors that affect the operation and
maintenance of the process:

 Maintenance Facilities

Trains require special facilities for storage and maintenance. The

basic design of these facilities as changed little in the last 100 or more years
and, in many cases, the original sites and buildings are still in daily use.
Sometimes, these old layouts have made adapting to modern maintenance
systems very difficult.
The layout of a maintenance facility or depot will consist of a storage
yard, a car cleaning area, an inspection and light maintenance shed, a heavy
maintenance shop and, possibly, a separate locomotive shop or at least an
area for locomotives if EMUs are the main service providers. A typical
facility with space for EMUs, works trains and locomotives might.

 Access

An essential feature of any depot is good access, for both road and rail. Good
rail access means that trains can get in and out of the depot without delaying trains
on the main line and without upsetting operations within the depot. It is no good if
a train coming in has to stop at the depot entrance while the driver gets instructions
from the shunter or depot control office and the rear of the train is still standing on
the main line. This can remove two or three paths from a timetable. Usually a long
access track into (and out of) a depot is required, if space is available. If the
railway is equipped with ATP (Automatic Train Protection), the changeover
between ATP and manual operation will probably have to take place on this track.
This must be carefully incorporated into the depot track design.

 Cleaning and Stabling

Trains are stabled in depots or sidings when not in use and they need to be cleaned
and serviced.  Cleaning means a regular exterior water wash and interior sweeping
and dusting or vacuuming.  At longer intervals, seating upholstery and carpets
must be shampooed.  Exterior washing is usually means a drive through washing
machine which will wash the sides and, perhaps, the roof.   Suitable facilities must
be provided in the stabling areas where trains are stored.  Water, power and toilet
cleaning systems need to be provided in such areas, adjacent to each train to be
serviced.  Access to trains must be designed so that cleaning staff can reach them
safely whilst carrying their equipment.  This usually means floor height walkways
alongside trains, or at least up to the first car of a set if through inter-car
connections are available.
 Train stabling areas are traditionally outdoors largely because of the expense of
constructing large sheds.  However, covering the stabling areas with some sort of
weather proof structure is always preferable.  It protects the trains and the staff
working on or around them and reduces contamination by pollutants, frost, snow
and wind damage.  A covered area will also provide some benefit in hot conditions
and could help to reduce the air conditioning costs.

 Toilets

Modern trains which have toilets need to have them serviced regularly. 
Although not shown in the above layout, a toilet discharge facility is required in
any depot where trains have toilets.  The discharge has to be done away from the
main buildings and where there is road access for the removal of effluent if it
cannot be disposed of on site.  Emptying of effluent tanks is normally followed by
rinsing and then recharging of the system with flushing water containing
formaldehyde to break up the waste matter.

 Leaves on the Line

One of the major sources of wheel damage in temperate climates with decidious
trees is fallen leaves. 

Fallen leaves really can disrupt rail services, –not just here in Britain, but all over
Europe and North America. The scale of the leaf-fall problem and the cost of
keeping services running smoothly is huge: 

 a mature lineside tree has between 10,000 and 50,000 leaves thousands of
tonnes of leaves fall onto railway lines each year 
 there are 20,000 miles of track to keep clear in Britain
 the annual cost of repairing damage to trains and track from leaf fall is over
£10 million
 lineside vegetation management costs over £5 million each year
 the cost of felling large trees is between £20,000 and £50,000 per mile. 
  Inspection Sheds

Special facilities are required to carry out rolling stock inspections (Figure 6). 
A properly constructed building, capable of accommodating a whole train, should
be provided.  Access to the underneath of the train is essential and this must be
designed to allow reasonable working conditions and safety.  There are various
ways of doing this.  The most common used to be a pit provided between the rails
of the maintenance tracks and, sometimes, pits on either side of the track as well,
to allow access to the sides of the underframe equipment.  A more common
approach today is the "swimming pool" design, where the floor of the shed is sunk
and the tracks are mounted on posts.  This gives better access and improves the
light levels under the cars.

 Lifting
The traditional method for accessing bogies was to lift the car body off the
bogies by use of an overhead crane or cranes . With overhead cranes, each
vehicle to be lifted has to be separated from its fellows in the train first and
 dealt with separately.  If one car in a set is defective, it has to be uncoupled and
pushed into the shop for lifting.  To access the bogies, the overhead crane is
used to lift one end while the bogie is rolled clear and then the body is lower
onto stands.  Then the other end is lifted, the bogie rolled clear and the body
lowered onto two more stands.  A quicker method is to use two cranes together
which lift both ends of the car body together and free both bogies at the same
time.  The body can then be removed to another part of the workshop for
maintenance. Motors, wheels and other items can then be worked on or
removed from the bogie as necessary.  Naturally, this takes up a lot of track
space in the shop and requires time spent on separating the vehicle from the
train and then from its bogies.  For overhauls, the bogie may be removed to a
special area where it is placed on stands for stripping and refitting work.

Jacks are the usual method of lifting nowadays. Vehicles can be lifted
individually or, if a fixed formation is used for normal service, more recent
practice has been to lift the whole train set.  This is done by synchronised jacks. 
The jacks are linked by control cables and controlled by one person from a control
desk.  The big advantage of this system is that you don't have to break up the train
into individual cars to do the work on one vehicle.  The time saved reduces the
period the train is out of service. Jacks may be mobile, linked by cables to a control
desk so that they may be operated together, all built into the workshop floor where
again the lifting system is synchronised to allow several cars to be lifted at the
same time if necessary.

 Maintenance Programmes

Rolling stock maintenance can be programmed in one of three ways; by

mileage, by time or by conditioning monitoring.  Of these three methods, condition
monitoring is the most recent.  Traditionally, maintenance was carried out on a
time basis, usually related to safety items like braking and wheel condition.  Many
administrations later adopted a mileage based maintenance system, although this is
more difficult to operate as you have to keep records of all vehicle mileages and
this is time consuming unless you have a modern train control and data gathering
system.  There is also the fact that a train will deteriorate just as quickly if it is
stored unused somewhere as it would if it was being run in service every day. 
Only the items which deteriorate will vary.

 Prediction

Modern asset maintenance management should examine the potential risks of

failures occurring in rolling stock using a failure mode, effects and criticality
analysis (FMECA) approach. The most critical failure modes in the system with
respect to both reliability and economic criteria need to reviewed, the levels of
failure criticality determined and possible methods for mitigation provided. 

A railway comprises two main assets: infrastructure and rolling stock. There
has always been much interest in the study and analysis of infrastructure failures,
e.g. track, bridges, train control, electrical systems, etc. However, few attempts
have been made by researchers to develop failure criticality assessment models for
rolling stock components.

 The Development of Train Maintenance

The regular inspection of motive power, coaches and wagons has long been a
part of the railway culture.  The need for visual inspections was based on the need
to ensure the good condition of the structure of the largely wooden bodies of the
coaches and wagons and the integrity of the wheels, axles and braking systems. 

Traditional visual inspections and manual checking with gauges has been
replaced by automatic inspection systems that compare wheel profiles of vehicles
passing through an inspection building with computer based data profiles.
Trackside systems are also used to monitor wheel behaviour. Similar systems are
used for bakes pads, discs and pantographs for current collection. On-board
systems provide train system performance checks and report to the maintenance
centre via wifi downloads at regular intervals.
Bibliography

 http://www.diva-portal.org/smash/get/diva2:991165/FULLTEXT01.pdf

 http://www.railway-technical.com/trains/train-maintenance/

 https://www.american-rails.com/railroad-maintenance.html

 https://www.sciencedirect.com/science/article/pii/S2352146515001982