dissenting.
I respectfully dissent.
Leslie Rouse suffered a foot injury when the toes on one of her feet were entrapped at the bottom of an escalator she was descending at a transit station owned and operated by the Metropolitan Atlanta Rapid Transit Authority (MARTA). Rouse sued MARTA and Millar Elevator Service Company (which maintained the escalators at the station under a contract with MARTA) claiming that MARTA negligently failed to keep the escalator in a safe condition for its passengers and that Millar negligently failed to carry out its contractual duties to maintain and repair the escalator. The trial court granted summary judgment in favor of the defendants and Rouse appealed.
Because escalators and other mechanical devices sometimes get out of working order and cause injury without negligence on the part of anyone, Rouse cannot rely on the doctrine of res ipsa loquitur to establish a presumption of negligence arising solely from the fact that her foot was entrapped in the escalator; rather she must produce evidence to support her allegations that negligence by the defendants in the maintenance or repair of the escalator caused her injury. Sparks v. MARTA, 223 Ga. App. 768, 770 (478 SE2d 923) (1996); Millar Elevator Svc. Co. v. O’Shields, 222 Ga. App. 456, 457-458 (475 SE2d 188) (1996). MARTA is not an insurer of its passengers’ safety while using escalators; it is, however, held to the elevated standard of care applicable to common carriers — the duty to exercise extraordinary diligence to protect the lives and persons of its passengers. Sparks, 223 Ga. App. at 768. Moreover, MARTA cannot avoid this duty by contracting with a third party, such as Millar, to maintain and repair the escalator. Gaffney v. EQK Realty Investors, 213 Ga. App. *625653, 655 (445 SE2d 771) (1994). When the duty to exercise extraordinary diligence is imposed, only slight negligence need be shown. Id. As to the standard of care imposed on Millar in its capacity as the escalator servicer, we have at least impliedly held that more than ordinary care is required because “such a standard would be heightened due to the risk of injury posed to those traveling on an escalator.” O’Shields, 222 Ga. App. at 458.
Even assuming Millar is held to the same extraordinary diligence standard applicable to MARTA, there is nothing in the present record showing even slight negligence by MARTA or Millar sufficient to establish a violation of the standard of care. Rouse alleged in her complaint that the defendants negligently operated the escalator with a gap at the bottom of the escalator that allowed her foot to become entrapped under the teeth of an escalator part known as a comb plate located where passengers step off the escalator. Rouse testified at her deposition that she was wearing canvas-type shoes and that, as she attempted to step off the escalator, her shoe got caught and was pulled under the comb plate up to her toes. However, Rouse also testified that she did not see any sort of gap at the bottom of the escalator, and there was no other evidence that the escalator was otherwise out of repair or was being operated with an improper gap at the comb plate. Furthermore, there is no evidence in the record that MARTA or Millar failed to inspect, maintain, or repair the escalator at issue and, other than the incident itself, no evidence that the escalator malfunctioned.
The evidence showed that a Millar mechanic performed regularly scheduled maintenance on the escalators every month and that the monthly maintenance was performed on the escalator at issue 13 days prior to Rouse’s accident. The mechanic deposed that, when he performed the monthly maintenance, there were no parts on the escalator requiring repair at that time and no other problems with the operation of the escalator. Other evidence showed that all the escalators at the MARTA station were observed on a daily basis by a Millar mechanic for possible problems and that no problems were reported on the escalator at issue in the days leading up to the accident. About seven days prior to the accident, another Millar mechanic performed repair work on the escalator at issue which included replacement of a lower comb plate. The repair work was re-checked four days prior to the accident to confirm that the comb plate was functioning properly. The mechanic who performed the repair also confirmed that on a daily basis he rode and visually inspected the escalators, including checking the comb plates to insure they were functioning properly, and that his daily inspections leading up to the accident revealed no problems with the escalator at issue. The mechanic who performed the monthly maintenance on the *626escalator deposed that on the day of the accident a few hours prior to the accident, he visually examined the escalator at issue, looked at the comb plates, and traveled up and down the escalator, and that he saw no malfunctions at that time.
Rouse’s testimony that she thought a yellow plastic flap that covered the comb plate was missing from the escalator was not sufficient to create an issue of fact with regard to her claim that the defendants negligently maintained or repaired the escalator. The defendants provided expert testimony from a trained and experienced escalator mechanic that no such flap has ever existed as a part covering comb plates on the escalator at issue or on other escalators. Moreover, the same expert mechanic testified that he arrived at the scene of the accident while Rouse’s foot was still entrapped under the comb plate and that the escalator was not missing any parts. Rouse’s lay testimony was not sufficient to create a factual issue in the face of expert testimony from an escalator mechanic that no such part existed on the escalator and that, at the time of the accident, the escalator was not missing any parts. Whether or not a particular mechanical part exists in the machinery of an escalator involves specialized expert knowledge possessed by those with appropriate education or training, and is not within the ken of laypersons with no such education or training. Harrell v. Lusk, 263 Ga. 895, 896-897 (439 SE2d 896) (1994); Sorrow v. Seloff, 177 Ga. App. 87-88 (338 SE2d 482) (1985) (expert testimony that absence of protective part on machinery was not apparent to layperson without mechanical expertise).
Rouse also claimed that an affidavit from a cousin who was with her at the time of the accident created an issue of fact. The cousin stated that, when she heard Rouse scream, she rushed down the escalator and saw that Rouse’s foot was entrapped at the bottom of the escalator. She stated that “[w]hile people were trying to stop the escalator and get her foot out, I noticed the escalator was chipped and cracked.” At best, this attempts to provide circumstantial evidence in support of Rouse’s claim that negligent maintenance or repair of the escalator caused the accident. When a party relies on inferences from circumstantial evidence to prove a claim, the inferences must not only in some proximate degree tend to establish the conclusion sought, they must also render less probable all inconsistent conclusions. Page v. Atlanta Center Ltd., 219 Ga. App. 422, 424 (465 SE2d 456) (1995). Amere inconclusive inference, or one that raises only a mere conjecture as to the conclusion sought, is not a reasonable inference sufficient to create an issue of fact. Allen Kane’s Major Dodge v. Barnes, 243 Ga. 776, 781 (257 SE2d 186) (1979). The defendants provided evidence that they properly inspected, maintained, and repaired the escalator, and that the escalator was functioning properly on the day of the accident a few hours before it occurred. In light *627of this evidence, a nonspecific reference to chips or cracks somewhere on the escalator is not sufficient to support a reasonable inference that the accident at issue was caused by negligent maintenance or repair of the escalator. This evidence does not render less probable the conclusion that the accident was caused by either a sudden mechanical malfunction or an inherent risk in the use of the escalator that was not the proximate result of any negligence by the defendants.
It follows that, because there was an absence of evidence in the record that the accident was caused by any negligent failure of the defendants to maintain or repair the escalator, the trial court properly granted summary judgment to MARTA and Millar. Lau’s Corp. v. Haskins, 261 Ga. 491, 495 (405 SE2d 474) (1991).
The majority finds that an issue of fact remains as to whether the duty to exercise extraordinary diligence would have required the defendants to add a safety feature to the escalator which was not a part of its original design. During the deposition of a former Millar mechanic, the mechanic was questioned by Rouse about the existence of a safety feature, known as a comb plate impact switch, which had been incorporated into the design of escalators manufactured after the escalator model at issue. According to the mechanic, a comb plate impact switch is designed to cut off the escalator when a certain amount of force is exerted against a comb plate. The mechanic testified that the code applicable to the escalator does not require that comb plate impact switches be installed on older escalators as part of regular maintenance and repair, but that the code does require installation of the switches when improvements or upgrades are made to existing escalators. The record shows that the escalator at issue is a Westinghouse model originally installed at the MARTA station when the station was constructed in about 1980. There is no evidence in the record that any type of improvements or upgrades have been made to the escalator which would have required the addition of the comb plate impact switch under the applicable code.
This case does not involve a claim that the escalator at issue was defectively designed when it was manufactured. Rather, Rouse’s complaint alleged that the defendants negligently failed to maintain or repair the escalator as it was designed. The defendants moved for and were granted summary judgment on this issue. In response to the motion for summary judgment, Rouse argued that there was evidence sufficient to show that the defendants negligently maintained or repaired the escalator as it was designed. Rouse did not allege in her complaint, nor did she argue in response to summary judgment, that the defendants had a duty to add a safety feature to make the escalator safer than its original design. Even though Rouse questioned a mechanic at a deposition about the existence of a safety *628feature which could have been added to the escalator, she never raised this issue in her pleadings and the trial court never ruled on it.
Accordingly, the majority’s conclusion that a factual issue remains on this claim is erroneous for two reasons. First, the claim that the defendants failed to add the safety feature was not raised or ruled upon in the trial court, so it presents nothing for appellate review. Pfeiffer v. Ga. Dept. of Transp., 275 Ga. 827, 829 (573 SE2d 389) (2002).
The purpose behind summary judgment is to dispose of litigation expeditiously and avoid useless time and expense to go through a jury trial. This purpose is thwarted when a party may withhold meritorious legal arguments until appeal. Allowing a party to raise new arguments also ignores the duties and responsibilities placed on the parties by OCGA § 9-11-56. Each party has a duty to present his best case on a motion for summary judgment. This Court has specifically held that, in responding to a motion for summary judgment, plaintiffs have a statutory duty to produce whatever viable theory of recovery they might have or run the risk of an adjudication on the merits of their case. The same burden is placed on the parties with regard to factual issues. As we held in Lau’s Corp. v. Haskins, once a defendant points out that there is an absence of evidence to support the plaintiffs case, the burden then shifts to the plaintiff, who must point to specific evidence giving rise to a triable issue. Additionally, our appellate courts are courts for the correction of errors of law committed in the trial court. Routinely, this Court refuses to review issues not raised in the trial court. To consider the case on a completely different basis from that presented below would be contrary to the line of cases holding, “He must stand or fall upon the position taken in the trial court.” Fairness to the trial court and to the parties demands that legal issues be asserted in the trial court. If the rule were otherwise, a party opposing a motion for summary judgment need not raise any legal issue, spend the next year thinking up and researching additional issues for the appellate court to address, and require the opposing party to address those issues within the narrow time frame of appellate practice rules.
(Punctuation and footnotes omitted.) Id. at 828-829.
Second, even if this claim had been properly raised below, it has no merit. As to Millar, there is no evidence in the record that its maintenance contract with MARTA included a responsibility to add *629safety features to the existing design of the escalator. Moreover, contrary to the majority’s finding, the duty to exercise extraordinary care in the maintenance or operation of the escalator did not include a duty to add a safety feature which was not a part of the escalator’s original design. Darlington Corp. v. Finch, 113 Ga. App. 825, 827-828 (149 SE2d 861) (1966).
[O]ne is not required to furnish the latest or best appliances, or to incorporate in existing equipment the latest inventions or improvements even though such devices may make the equipment safer to use. An appliance is not defective by reason of the failure to have incorporated therein the latest improvement or invention developed for its use. It is not incumbent upon persons or corporations using machinery in the prosecution of their business to procure the very best and safest machinery which can possibly be made. It is sufficient if the machinery is of a kind in general use, and reasonably safe for all persons who operate it with ordinary care and diligence.
(Citations and punctuation omitted.) Id. Since the escalator at issue met these standards, the failure to add a safety feature to make the escalator safer than its original design cannot be considered negligent under the applicable standard of care.
By overruling Finch, the majority places upon MARTA and similarly situated buyers of nondefective products a duty not only to keep the products as designed in safe working order, but also a post-sale duty to stay constantly informed of technical advances in product design and manufacturing and to incorporate those advances into previously purchased products to make them safer. Although manufacturers have a post-sale or continuing duty to warn of defective products after they have been manufactured and sold if the manufacturer knows or reasonably should know that a product has been sold with a dangerous defect, the duty is premised on the manufacturer’s product expertise which enables it to learn of defects and devise corrections. Chrysler Corp. v. Batten, 264 Ga. 723, 724-725 (450 SE2d 208) (1994); Thorpe, Venderbush, and Neal, Ga. Products Liability, 3rd ed., § 8-7, Post-sale duty to warn. The effect of the majority opinion is to place an even more expansive duty on buyers, even if there is no evidence the product was defectively designed, and even though buyers lack the expertise of manufacturers. The majority places an impossible burden on MARTA and similarly situated buyers and makes MARTA a virtual insurer of passenger safety.
I am authorized to state that Chief Judge Smith, Presiding Judge Johnson, and Presiding Judge Ruffin join in this dissent.
*630Decided March 29, 2004 Hinton & Powell, Andrew J. Hinton, Jr., for appellant. Lokey & Smith, Malcolm Smith, Kevin A. Doyle, for appellees.