|The rear of the San Joaquin Daylight as it enters Tunnel No.2, west of Allard on Tehachapi Pass, La Mesa Model RR Club.|
The first consist of MTH cars I worked on in 2011 was built for the La Mesa Model Railroad Club's operating fleet, and upgraded to the mechanical standards of the club. I will cover the San Joaquin Daylight in more detail later, when I do a blog specifically on the consist of the San Joaquin Daylight. This is a general page is for modelers that want to see what upgrades I suggest to improve operations with the MTH models.
I have several other projects working on single cars and additional upgrades to various aspects of those models. Those upgrades I do not consider to be ones I would make to every MTH Daylight car, so they will be covered in individual blog posts on those cars. Any new upgrades I start on that I plan to do on every MTH Daylight car, I will update this page in the future.
The Morning Daylight became the Coast Daylight after the Noon Daylight was discontinued. These cars can also be the basis for building consists for the San Joaquin Daylight (51/52), Starlight (94/95), Sacramento Daylight (53/54), Morning/Coast Daylight (98/99), and Noon Daylight (96/97) which I will go over in more detail in other posts. I will be referring to Trains 98 (eastward) and 99 (westward), the Morning Daylight and Coast Daylight, which are really the same train.
Here are two YouTube videos of the MTH consist running around at the La Mesa Model Railroad Club as the San Joaquin Daylight as No.51 (westward) and No.52 (eastward).
UPDATE EDIT - Oct 2019
TSG filmed a video of my modifications to the MTH Daylight cars. Enjoy!
The 8-car MTH "Core" Set
The MTH sets that were offered for sale in 2011 consisted of 8-cars, which would be best used to create a post-1941 Morning Daylight.
Historical Overview of the Models Offered by MTH and BLI
In detail the MTH cars are as follows:
79-CB-1 Combine - Dec 1939 built (SP 3303)
|Left side of SP 3302 with new extended "SOUTHERN PACIFIC" decal added|
The MTH set lists this car as a "Baggage" in the box, while it is clearly a combine. These 79 foot cars were built to re-equip the Morning Daylight. The Noon Daylight and Starlight never used a combine in its consist. The San Joaquin Daylight received the transferred 1937-built 77 foot combines in 1941. This means that the 79-CB-1 models are really only correct for modeling the 1939-1958 Morning/Coast Daylight.
79-C-1 Chair - 1939-built (SP 2439)
|Left side of SP 2439 with out-of-box letter board "SOUTHERN PACIFIC"|
The first batch of 79 foot chair cars for the Daylight pool were delivered in December 1939 as part of the batch of cars ordered to increase the size of the Daylight pool after the booming success of the 1937 debut of the streamlined Daylight. I discuss more about this class below with the Add-On Cars.
Triple-Unit Diner-Kitchen-Coffee Shop - 1941 built (SP 10259-10260-10261)
Overview of Triple-Unit Diners
The SP had four Articulated Diners (AD), two built in 1939 and two in 1941. They're grouped as 70-AD-1/2 for the 1939 cars and 70-AD-3/4 for the 1941 cars with Kitchen units classed as 57-AD-1 for the 1939 cars and 57-AD-2 for the 1941 cars. The 1939 cars differed in that their kitchen-units only had one door, centrally located on the left side. This was not changed until 1955 when the SP 10253-54-55 set emerged from the SP shops as a Coffee Shop-Hamburger Grill car. The SP 10250-51-52 never re-entered service after 1954 with this upgrade.
|(Front) Coffee Shop Unit, 1941-built 70-AD-4|
This resulted in the 1939 built sets being setup in 70-AD-2 = 57-AD-1 = 70-AD-1 triple unit configuration. The 1941 built sets configured as 70-AD-4 = 57-AD-2 = 70-AD-3
|Left side of (Middle) Kitchen Unit, 1941-built 57-AD-2|
|(Rear) Diner Unit, 1941-built 70-AD-3|
The first two 1939 sets had Coffee Shops SP 10252 & 10255, Kitchens SP 10251 & 10254, and Diners SP 10250 & 10253. The 1941 cars were Coffee Shops SP 10258 & 10261, Kitchen SP 10257 & 10260, and Diners SP 10256 & 10259. While these articulated diners were bi-directional, the "Normal" direction these sets ran was with the kitchen doors on the left side of the train (the same as the earlier HW and LW dining cars), and the Coffee Shop forward of the kitchen.
The 1941 set that MTH decided to model, the SP 10259-10260-10261 were reassigned in 1950 to protect the Shasta Daylight's new triple-diners built in 1949. The SP's 1937-built Daylight diners 10200 and 10201 were used on various assignments over the years, moving between the Overland Limited, San Joaquin Daylight and Noon Daylight, with HW Diners and lounges protecting the San Joaquin Daylight assignments when an articulated diner or the 10200/10201 were not available.
Link to my blog post kitbashing the 1939-1954 version of the SP Artic-Diner 10250-51-52 (Part 1).
70-AD-4 Coffee Shop - (SP 10261)
The coffee shop unit these units were similar to the Diner units, but with coffee urn and drink station in the middle section of the car behind the wide column. The tables usually were not covered with table cloths.
When a pair of these cars were assigned to San Joaquin Daylight during the off season, the coffee shop unit was converted to lounge seating when the Taverns were removed from the consist.
Notice in the above photo of the Coffee Shop the tables are bare and show the multi-colored tile patterns.
The SP Coffee Shop and Dining Cars didn't actually have any physical differences that made them a Coffee Shop other than the menu and what supplies were loaded into the kitchen and pantry for the assignment. However in photos it seems that the Coffee Shop cars did not use white linen table cloths, but left the tables exposed, as many coffee shops today do.
In later years the SP began doing more changes to the physical layout of food service cars, such as the Hamburger Grill cars (1954), Snack-Lounges (1955 Lark), etc. which were a change of service and menus.
57-AD-2 Kitchen - (SP 10260)
The kitchen unit for the 1941 design. The the second 1939 units, 57-AD-1, SP 10254 was upgraded to have the three access and loading doors configuration in 1954-55, so these are really only correct for the 1941 cars SP 10257 & 10260 until 1954. Before the 57-AD-1s were rebuilt, they had two pain loading windows in place of the outer pantry doors.
|Right side of Kitchen Unit, 1941-built 57-AD-2|
The kitchen unit has a centrally located kitchen, which has pantries on either end. The forward pantry serves the Coffee Shop unit and the rear pantry serves the Dining unit.
|Interior detail of 57-AD-2, front being to the left.|
As with all the MTH cars, the Kitchen-Unit has a full interior. On some models I've used a slight dark wash over some of the relief details on the stoves, etc to bring them out a little bit. On one car I added a couple of cooks in the kitchens and some various things around the stoves and preparation areas. Mostly this can't be seen from the exterior of the car, unless you get at just the right angles in low enough lighting to see inside. I would actually say this is one place to use "Cutout" forms of figures, painted with contrasting colors (white uniforms) compared to the stainless steel surfaces of the kitchen.
The roof of the Kitchen also has a lighting bar with LEDs, which picks up power through the trucks from the 70-AD-3/4 Coffee Shop and Diner units on each end. The 6-wheel articulation joint trucks do not pickup power.
70-AD-3 Diner - (SP 10259)
The Dining unit is fitted with 18 four seat tables which are served from the adjoining kitchen unit. The dining unit is where the fine dining is done normally. The tables all have white linen table cloths on them, while the Coffee Shop usually did not.
79-T-1 Tavern - 1939 built (SP 10315)
The 1939 Daylight upgrades received second pair of new taverns for service on the Coast Daylight and two slightly smaller 1938 77-T-2 cars were assigned to the Noon Daylight assignments. They were stored during WW2 and rehabilitated in 1945 and returned to service. The extra cars moved around between various assignments through the 1950s on the San Joaquin Daylight, Starlight, and Noon Daylight.
|SP 10315 in service|
The Taverns were fitted with a 'color wheel' lighting system which changed the color of the lighting over about 30 seconds. I was able to upgrade the model to simulate this with a 3-color LED with a built in color changer, similar to what night-lights have in them. - I plan to show this at a later date when I blog about modeling the Tavern in detail.
79-PR-1 - 1941 built (SP 3003)
The 1939 upgrade to the Coast Daylight included a new pair of 1st class parlor cars, SP 3002 and SP 3003. These two cars spent their carriers until rebuilding into chair cars nearly exclusively assigned to the Coast Daylight.
79-PRO-1 - 1941 built (SP 2951)
The upgrades to the 1st class part of the Coast Daylight included a pair of new parlor observations.
MTH seems to have goofed on the car number, as the SP 2950 and SP 2951 were both 77-PRO-1s without baggage elevators built for the 1937 Daylight. The 79-PRO-1s should be numbered SP 2952-2955.
MTH sells extra Chair cars to expand the basic 5-car set or 8-car set to full prototypical length consists.
79-C-1 (& 79-C-2) Chair cars
MTH also offers the single-unit 79-C-1 Chair Cars separately, unfortunately only the SP 2440 is available. This car is discussed above.
|Right side of SP 2439 and SP 2440 offered by MTH|
The 79-C-1 class cars are the same as 79-C-2 follow-on class which was delivered in May 1941. I plan to use these extra cars to model some of the 9 cars in the 79-C-2 class, numbered SP 2485-2493. While I'm not going into extensive detail about the 79-C-2 class cars here, I will briefly touch on which trains they were built for and to mention that they were not all the same, which lead to some of them being assigned to trains using cars outside of the Daylight pool.
The first two 79-C-2s were built for the Coast Daylight (SP 2485 & 2486). The SP 2489-91 were built without baggage elevators and painted Dark Olive Green for the Challenger. These tended to stay assigned to the Overland-route trains. The 2487, 2488, 2492, 2493 were built for the San Joaquin Daylight with the train herald on the shield plaque.
The 79-C-2s were repainted several times over the years as they're moved between various assignments. I plan to eventually convert a MTH car to the non-elevator version chair car and repaint the car out of Daylight colors.
66-ACM-1/2 and 66-ACW-1/2
The 130ft Artic Chair cars that MTH makes add-on cars that are bought separately to fill out the Daylight consist that you want to model. The AC is for Articulated Chair and the M is for men's restroom cars with odd #s and the W is for women's restroom cars with even #s.
|SP 2447 ACM - Articulated Chair Men from MTH (Odd #'s)|
|SP 2448 ACW - Articulated Chair Women from MTH (Even #s)|
The 66-ACM/ACW-1s were numbered 2441-2451 delivered in 1939 with steam A/C systems. The 66-ACM/ACW-2s were numbered 2457-2483 and were delivered in May and April 1941 with Waukesha propane A/C systems. The main difference between the 64-ACM/ACW 1937 articulated chair cars and the 1939 and 1941 cars is the addition of the baggage elevators.
The 66-ACM/ACW-2 cars were assigned as follows in 1941: SP 2457-2476 to the Coast Daylight and SP 2477-2483 assigned to the newly streamlined San Joaquin Daylight (SJD). The special "San Joaquin Daylight" insignia was dropped in 1946 and replaced with the standard "Daylight" insignia and assigned to the general Daylight pool. While it would be fun to model the cars with the SJD insignia for the post 1946 trains, I am not going to do that. This also gives the option to choose a wider selection of car numbers for a consist as the cars were pooled, there was still some attempt by the SP to keep cars with steam A/C assigned to the cooler Coast Route Daylight assignments.
SP 2445-2448 were changed to Waukesha A/C systems in 1950, followed in 1951 by the SP 2451-2452 set. SP 2441-2442 were converted in 1958, SP 2443-2444 and SP 2449-2450 sets in 1961.
I will go over modeling specific Articulated Chair cars from these classes in more detail separately.
Mechanical & Lettering Overview
Both MTH and BLI have produced the same 1939/1941 Daylight passenger cars. Why two companies race to get the models of the same prototype cars on the market with in 2 years of each other is rather strange. Much the same as the 8+ models of EMD F7s that are on the market as well. I will be looking solely at the MTH models that I've worked on over the last 5 years.
Starting off with the mechanicals, these cars are arguably the better model on the market right now.
|Bottom with detailed underframe on MTH 79-C-1 chair car|
The trucks are mounted with screws, which allow for adjustment and ease of removal for maintenance. This is important also to be able to clean the wiper post contacts of the electrical pickup system for the car's lighting system.
|MTH 79-C-1 truck and coupler|
The draft gear boxes for the couplers are also secured by screws, which can be set in one of two positions: either scale close coupled (with the diaphragms touching) or extended coupled (with a gap between the diaphragms) for use on tighter radius curves.
The articulation joints of the multi-unit cars (Articulated Chair cars and the 'triple-unit' diner-kitchen-coffee shop car) is made with a bar across the truck and a pin on one of the unit bodies that securely holds the units in either the close coupled or extended coupled positions, much like the coupler boxes. This design is far superior to the BLI's friction snapped-on drawbar system.
I have seen BLI trains of no more than 6 or 7 cars break in two at the articulation bar joints on a 2.2% grade. This is less than 1/2 what a full San Joaquin Daylight consist is and only about 1/3 what a full Coast Daylight consist would be.
|Full-width Diaphragm on MTH chair car|
The diaphragms of the MTH cars are better in my opinion too. The MTH cars are equipped with rubber full-width diaphragms (FWD) on both ends of each car, except the combine and observation car of course. These have an etched metal striker plate which is painted and has extra detail. These diaphragms need only small adjustments to clean off burrs to operate reliably.
I usually use a small flat diamond file to clean the edges of the striker plate etching to remove any burrs from the edge. Sometimes these burrs will catch on the adjoining car and cause the end of the car to bind up, derailing the train, sometimes at the other from where the bind has occurred.
|MTH cars on 48" radius curve with "close-coupled" articulated ends|
The articulated ends of the cars have one extra long diaphragm spanning the gap. The prototype cars had diaphragm material that spanned the full gap as well, however even the real ones tended to tear when in service. With in a few years the prototype cars were re-equipped with a standard length FWD on the articulated end of each unit. It would have been nice if MTH had done this as well, but I'm very happy with the job they did.
The BLI cars on the other hand use a hard plastic "shell" which is nicely painted to match the car sides, but when the cars enter a curve, the "shell" opens at the ends of the car bodies to reveal a black inner screen or view block. I feel this visually detracts from the BLI cars in a big way while in operation.
I'm working on models detailed for operation after June of 1946, when the SP changed the main letter board from a narrower lettering "SOUTHERN PACIFIC LINES" (SPL) to only "SOUTHERN PACIFIC" (SP) in extended lettering.
|The MTH's incorrect 'narrow lettering'|
The main issue I have with MTH is that they botched this lettering change pretty badly. The pre-1946 lettering looks pretty much correct. However, MTH when they did the artwork for the post-1946 lettering it appears they simply re-centered the "SOUTHERN PACIFIC" portion of the SPL lettering and dropped the "LINES" from the pad printing, but retained the narrower lettering.
I have not seen any indication that SP use the narrower lettering in this fashion on any Daylight equipment after 1946. The SP did use the narrower lettering on their Dark Olive Green painted cars where features of the car side, such as doors, made the use of the extended lettering impossible, but we're not discussing those applications in this post.
|Relettered "SOUTHERN PACIFIC" decal corrected MTH Chair|
Therefore the main detail change that needs to be done to the MTH cars, is removing the letter board lettering, touching up the paint, and applying new letter board "SOUTHERN PACIFIC" extended lettering decals from MicroScale 87-205 "Sunset Limited" set. This is not as difficult as it may sound and I will cover the method below.
Adding Weight - Better Tracking with FWD's
One of the additional things I do on most of the MTH cars to improve the tracking through curves is add some weight in the centersills of the cars.
|Coffee Shop unit with two strips of lead down the centersill and reattached water tank.|
This probably would not be needed on cars without the FWD's (Full-Width Diaphragms), but the FWD's tend to be a bit too springy sometimes and tend to bind enough that it can derail the cars if the curves are not eased or through switch work. I would also suggest diamond-burnishing the edges of the striker plates to remove any burrs that could catch on the adjacent car's FWD, as discussed above.
Truck Rebuilding and Re-gauging of Wheelsets
The wheels on the MTH trucks are very good rolling, some of the finest I've tested. Following are some photos of the rebuilding of the MTH trucks.
|This is the top of the out-of-box MTH triple-bolster truck with the pickup bars for powering the lighting|
|Bottom view of the out-of-box MTH truck|
While these trucks work very well out of the box, the wheelsets suffer from the same slightly tight wheel gauge that all wheelsets do at this time, where the back-to-back distance of the wheels is on the tight side and barely fit into the NMRA Mk-IVb gauge. Most wheelsets now also have sub-RP-25 contour flanges, which means the flanges are actually a bit on the tight side, as they are narrower than what the standards call for.
The easiest way to fix this is to spread the wheel gauge about 0.01" so that one side of the wheel gauge (say the left side of the notch) and contacts the left side of both wheels at the same time when in the gauge. This is the most practical way to gauge the wheels that are sub-RP-25 contour.
One problem with re-gauging passenger car truck wheelsets is that with the split axle power pick up design and plastic axle, the wheelset will grow in length by the amount the gauge is spread. This often causes the wheelsets to bind up in the sideframes. While the Walthers metal passenger trucks I use on most of the models I work on can be disassembled and the wheel reamer took can be used to make the journal bearing cones deeper, that will not work on the MTH Daylight cars because they use bronze/brass insert bars stamped with a different cone angle than the NWSL reaming tool. The MTH trucks and wheels use a much finer point which roll REALLY well. I prefer to modify the trucks using a method I was shown to increase the rolling qualities of the similarly regauged Kato ASF A-3 trucks and wheels in which the sideframes are bent outward, away from the wheelset, allowing it to roll freely. The MTH trucks require some modification to this plan, as I will describe below.
I will go through the process that I used on the MTH cars to spread the wheel gauge.
The first step is to remove the wheelsets from the truck to adjust the gauge. The MTH assembly techniques must use a jib to spread the sideframes, to safely get the wheelsets out, I found that cutting the end of the truck frames was enough to allow me to spread the truck enough to drop the wheelsets out.
|1st step - Cut end of the truck frame|
The plan will be to bend the metal pick up bars outward slightly (about 0.010" at the journal bearings). Cutting the end-frames of the trucks will allow the plastic truck frames to flex with the metal bars.
Step 3. Carefully spread the side frames of the truck away from the wheelsets and allow them to drop out. This should be easier to do now with the end-frames of the truck cut. You may wish to glue the brake hangers and brake cylinders more securely to the truck at this time to avoid loosing them if they come loose.
|Truck with wheelsets removed|
Step 4. With the wheelsets out, regauge them.
|Pick-up Bar Retaining Clip|
Step 5. Remove the plastic Pick-up Bar Retaining Clip (shown above). Do this by carefully prying the four small fingers away from the underside of the truck bolster with a small bladed flat screwdriver.
|Detailed view showing where to use screwdriver to remove Retaining Clip|
Step 6. Remove the Pick-up bars from the one-piece truck frame by moving them towards the bolster screw hole to disengage the bar from the mounting pin.
|Disassembled Truck showing all the parts spread out.|
Step 7. Take the Pick-up Bars and clean them with rubbing alcohol.
|Cleaning the Pickup Bars|
Step 8. Bend the Pick-up Bars slightly to the "outside" of the truck, away from the bearing surface of the bearing cones as shown below.
|Pick-up Bars - Straight (unbent) top and bent (modified) bottom|
Once bent the Pick-up Bars should all look like the one in the lower portion of the photo above. I also take this opportunity to paint the outer side of the Pick-up Bars black, making them less obvious when mounted on the car.
|Here's multiple cars worth of trucks, pick-up bars, retaining clips, and wheelsets being worked on.|
Once I'd determined the right amount of bend to get the re-gauged wheelsets to roll well (at less than a 0.3% grade!), I then did the rest of the whole train in one sitting.
|Rebuilt truck with blackened Pick-up Bar and Dullcoted.|
Step 9. Reassembly all of the trucks and return them to the cars. Do pay attention to the swing brace over the leaf springs that they're pointed the right way. I usually also paint the outer faces of wheels a dark gray-black color, which hasn't been done on the above models yet. See photos above for orientation.
Additional Work for the Triple Diner's Trucks & Wheels
This only leaves the Triple-unit Diner to work on, with its 6-wheel trucks.
|6-wheel Triple-unit Diner Kitchen truck|
Step 10. Remove the trucks from the Kitchen-unit.
Step 11. Carefully pry the sideframes apart and remove the wheelsets. The wheelsets on this truck do not pick up power, so this should be as simple as pulling one of the wheels on the axle out to the correct gauge.
Step 12. Check that the wheels roll freely. On the last Triple Diner I worked on, I had to do some light reaming with the NWSL Axle Reamer to get them to roll well.
Before June 1946 SP's passenger cars had "SOUTHERN PACIFIC LINES" spelled out on the letterboard in normal or "narrow" style letters and no car type was painted on the car.
|New lettering style after June 1946|
After June 1946 cars were repainted with "SOUTHERN PACIFIC" spelled out on the letterboard in "extended" style letters.
MTH's main failing on the 2011-2012 produced models is that they used the "narrow" pre-1946 lettering on the post-1946 lettered cars. This means that the letterboard lettering needs to be replaced.
|Addition of car type lettering, in this case "CHAIR"|
SP passenger cars after 1946 also had the car type painted in small lettering at each end of the car on the letterboards. On cars of one type, all four corners would read the same car type, but on cars of a compound type, such as; Chair-Baggage, Pullman-Lounge, etc the type painted on the end of the car reflected the type of service that end of the car provided. For example: SP 3300-3303 would have "BAGGAGE" on the front baggage section and "CHAIR" on the rear of the car, just forward of the vestibule.
|Car type lettering, in this case "BAGGAGE"|
Cars in general service such as Coaches, HW Baggage cars, RPO and RPO-Baggage cars did not have this extra lettering applied.
|SP 5124, repainted for service on the San Joaquin Daylight, but no type lettering is applied to the letterboards.|
|Coaches, such as SP 2178, carry no type lettering|
However, some specially painted Baggage and RPO cars on premier trains such as the Sunset Limited, Shasta Daylight, etc did have type lettering applied at the ends of the letterboards.
Removing MTH lettering & Re-decalling the Letterboards
I will be back with more photos detailing this process soon.
|SP 3003 Parlor with the lettering removed.|
This process involves your favorite method to remove pad-printed lettering from a model. The Daylight cars are a bit tricker because you don't want to disturb the fine striping above or below the letterboard. In the past (4-5 years ago) I used a fiberglass brush to carefully and gently remove the lettering without going very much into the Daylight Red paint. I believe on one or two cars I had to do some minor paint touch up before decalling.
Rubbing Alcohol is another option or Testors Easy-Lift-Off, if you're careful to keep it from migrating over the whole carside!
Another option is to simply match a Daylight Red to the MTH paint, mask off the rest of the body and strips, and paint over the letterboard with a new layer of paint. Polly-Scale (out-of-production) or StarBrand (Lacquer-based) paints I've found are a good match for the MTH paint.
Train Radio Stanchions & Antenna
One of the new 3d printed parts from Owl Mt Models is the new OMM #4046 Antenna Stanchions for MTH passenger cars. The 4046 set has 22 stanchions in the set, so if you loose two, there's still enough for 4 standard Daylight cars. The MTH Stanchions tend to break, and the antenna wire tends to get easily bent and not be easy to straighten again.
|OMM 4046 Stanchion installed on MTH Daylight car roof.|
The Stanchion is notched at the top to accept a piece of wire soldered in place, I generally am using 0.008-0.015" wire. Generally I like to use 0.010" or at largest 0.012" wire, for a really fine-scale look 0.008" or smaller would be best.
|The end stanchion after soldering and trimming off the excess wire.|
I've found that tack soldering the end stanchion to the antenna first is a good idea, then mount the first stanchion to the roof and the other stanchions will solder up very quickly.
|Here's one of the middle stanchions with the wire installed.|
I pull tension through the antenna as I go to keep the wire taught. Then, after all the stanchions are soldered, I come back and cut the extra wire off the ends.
|New Train Radio Antenna installed on an MTH Daylight Combine.|
Remember to only use about 1 cubic millimeter of solder on the end of your 15watt iron, also pre-flux the wire and notch on the stanchion so the antenna will solder in instantly. Do any clean up with a 600-grit sanding stick to knock off any solder spikes and clean up the joint before painting.
That will do it for now on the MTH cars. I will be continuing to update the page as I work on a few more of these cars and take more photographs.
Links and Related Articles:
Modeling the Coast Daylight by Scott Inman. - Scott Inman did a very nice modeling presentation on the Coast Daylight using MTH cars comparing them against The Coach Yard models.
SP 10250-51-52 (Part 1) - Diner-Lounge 1949-1954
Installing a Track Cleaning Pad in an MTH Kitch-unit SP 10250-51-52 (Part 3)
Modeling Index SP Lightweight Passenger Cars
Train Radio Antennas & Stanchions - Upgrading MTH Daylight Cars