/ by Francesco Maria Cominoli /

Second and last part of the article written by international expert Francesco Maria Cominoli on the guidelines for roller coaster maintenance. The focus here is on the so-called ‘Equipment Tree’.

Part 2 /

The first part of this article concluded by stating that in order to manage all of the maintenance requirements of a ride (including roller coasters), clear and unambiguous reference must be made to the components that require such maintenance, even if only in paper form, if no other formats are available. In other words, we said, the ride needs to be broken down into a tree structure, called the ‘Equipment Tree.’

The following is an indicative and non-comprehensive example of an Equipment Tree referring to a fixed steel roller coaster with mechanical lift and several trains. The Equipment Tree, for the sake of simplicity, comprises 2 levels. Obviously, the person responsible will need to codify the positions as desired (numerical, alphanumeric, descriptive, etc.) so as to uniquely identify the part subject to maintenance. Usually the third level of detail is the end point, used mostly to allocate stoppages and faults with better precision.

The routine maintenance requirements of the roller coaster type chosen for this example are extremely complex:

The static part is similar to a welded and bolted grid structure. The stresses are static (own weight), impulsive and alternating fatigue (moving train) and finally thermal (thermal expansion). In Italy, temperatures can range from -20 to +60°C (and beyond) between a winter night in Bolzano and a summer afternoon in full sunlight in Catania. It goes without saying then that the stresses are cumulative.

The lift is similar to a mine shaft lift; in fact, the largest lift chains are actually mine chains; they must be lubricated, checked regularly and replaced when their elongation exceeds 3%.

The stresses on wheels, pivots and the structure of the trains are similar to those of aircraft undercarriages.

Finally, the position sensors, which are strategic for the safety and reliability of the system, are exposed to possible bad weather and fouling (bird nests and insects, cobwebs, waste paper etc.).

Examining once again the topic of preventive activities, divided between daily checklists and SMPs, we propose the breakdown of activities shown below, again purely as a non-comprehensive example, referring to the Equipment Tree example above. All the activities defined as “daily” are included in the pre-opening checklist, the others in the SMP.

The emergency activities (corrective maintenance or breakdowns) must be logged in a database, which will be used to refine and adjust the preventive activities and as inputs for the cost-benefit analysis of any improvement actions.

In practice, everything should be agreed on with the manufacturer; any changes or improvements however must be agreed on. 

LIFT

Chain: annually, check percentage of elongation (ovalisation of pins and bushings). Schedule replacement when exceeding 3%.

Chain: daily, visually check conditions/tension.

Chain: daily, check condition of the anti-friction elastomer coating on the support guide. In practice, this sub-assembly is a third level detail, which we have omitted here to avoid complicating an Equipment Tree that is intended to be educational.

Gear motor: daily, check drive pinion conditions and oil level.

Gear motor: monthly, check motor current draw. 

Gear motor: quarterly, check motor-joint coupling (focus on flexible coupling blocks and alignment).

Gear motor: annually, clean the motor and check terminal block tightening.

Chain lubrication system: daily, check flow rate, timer and oil level.

Proximity switch: daily, clean. Daily, functional check. Six-monthly, check cables, anchors and signal strength, replacing where necessary.

SECTIONS OF TRACK FROM 1 to n (sections between 2 columns). For each section:

Rails: annually, random NDT (non-destructive testing); magnetic particle inspection method recommended. Agree on a cyclical plan with the manufacturer or laboratory (qualified!) that will carry out the tests.

Column: annually, NDT on track-column anchoring saddle welds. See the previous point.

Diagonals: annually, randomly check bolted joints with torque wrench (tightening values provided by the manufacturer)

Structural nodes: same as above.

Plinth: NDT. Check conditions of concrete and tension bars, approximately ever 5 years (depending on environmental conditions) and in any case at least once every 10 years. Son-Reb method is recommended for concrete, and ultrasound testing of the length of anchor bolts. Check bolt tightening (all, 100%) with torque wrench.

Proximity switch: daily, functional check. Six-monthly, check cables, anchors and signal strength, replacing where necessary.

ARRIVAL/BOARDING STATION

Brake blocks from 1 to n (assumption: pneumatic brakes with bronze callipers and tubes acting on longitudinal ‘fin’ under coach): daily, visually check the mechanical conditions and clean the electro-pneumatic valves. Daily, functionality test.

Brake block from 1 to n: Six-monthly, NDT. Check for compressed air leaks with ultrasound detector (Airborne system recommended). Repair leaks at connections and tubes in the event of leakages.

Proximity switch: daily, clean. Daily, functional check. Six-monthly, check cables, anchors and signal strength, replacing where necessary.

Control console: daily, functional check.

Lighting system: daily, functional check.

Sound system: daily, functional check. Daily, check that at least one backup microphone is available (charged and working).

Entrance/exit turnstiles: daily, functional check.

COMPRESSED AIR SYSTEM

On the overall system: Six-monthly, NDT. Check for compressed air leaks with ultrasound detector (Airborne system recommended). Repair any leaks at connections immediately. Schedule any other work.

Compressor: daily, start-up and functional check. Periodically, checks required by law. In the absence of a backup compressor, it is recommended to provide a coupling for rapid connection of a portable emergency compressor. 

Emergency accumulators: daily, check pressure. Periodically, checks required by law.

Storage tank: same as above.

Dryer unit: daily, functional check and monitoring to prevent the formation of frost in bad weather (inspections throughout the year based on the maintenance personnel’s experience). Six-monthly, check gas. 

AC distribution manifold and pneumatic control panel: daily, check dryers and oilers. Daily, functional check on condensate drains (random).

POWER SYSTEM

Main electrical panel: daily, check doors are closed and not tampered with. Weekly, check filter panels on ventilation openings. Predictive maintenance. Six-monthly, check possible crown effects or trekking with panel closed and functioning using Airborne ultrasound system. Annually, with the panel open check for any hot spots by infrared thermal imaging. Annually, check terminal block and busbar tightening. Six-monthly, clean.

PLC: quarterly, check backup batteries and connections. Check and replace filter panels on ventilation openings. Monthly, check the UPS, if featured.

Panel cooling system: weekly, check filter panels on ventilation openings. Annually, check gas charge and control unit operation.

Panels for units 1 to n: 6-monthly, check terminal blocks and clean. 

Emergency backup generator: checks and start-ups as required by law. Daily, check the rectifier and starter battery charge.

COACH from 01 to n ON TRAIN from 1 to n

Safety bars and headrest: daily, check closing and start interlock in the event of failure to close. Daily, check padding. Six-monthly, clean closing mechanisms and check conditions and play.

Wheels: daily, check Vulkolan tread (visually). Daily, check lubrication of bearings if with oil cups.  

Chassis: NDT. Annually, check welding with magnetic particle inspection method (coach on the ground). Normally in the presence of the manufacturer.

Wheel and rocker arm pins: NDT. Annually, inspect and look for surface cracks and variations in cross-section with fluorescent penetrating liquids and Wood’s lamp. Normally in the presence of the manufacturer. 

Coupling system: daily, check conditions and conformity. Annually, check for ovalisation and play in coach-chassis pins, on the ground. Normally in the presence of the manufacturer. 

Braking fin: daily, check fixing and condition of the braking surface.

Traveling rides used in fixed installations

Often small-medium sized theme parks or long-stay fun fairs have rides, including top-of-the-range models, that are designed to be dismantled. In this case, maintenance problems may arise due to inspection and prevention activities, especially on older rides. The accessibility of certain components, in fact, was automatic during disassembly and the manufacturer did not need to worry about guaranteeing this in the best possible way during operation.

Still on the subject of roller coasters, the load-bearing structures are partly bolted and partly anchored to ensure rapid disassembly. There are no plinths and ground anchoring can be performed in many ways, which require specific checks.

Conclusions

When purchasing a ride, of whatever type, it is recommended to fully examine all aspects regarding its ‘maintainability’. Maintainability is a significant strategic value and should not be addressed with the short-sightedness of ‘lowest possible cost’. Otherwise, much, much more will be spent and lost during the ride’s working life.

No business saves money to repair a fault or even to carry out a modification-improvement that is well supported by cost/benefit analysis. Conversely, when it comes to actually spending to ensure faults do not occur (i.e. prevention), things change and business are less inclined to spend. Without prejudice to legal obligations, the most efficient way to minimise faults and their consequences is a prevention based as much as possible on checks, visual and instrumental controls (predictive or condition-based maintenance). In this case, the work carried out is actually needed and is performed when necessary.

Taken from Games&Parks Industry June 2019, page 78