DL&W #1631-1650 4-8-4 Class Q-4

I found some info on the class in general but not anything pertaining to an "original" version and a "modern" version or maybe it was refined/rebuilt?

Can anyone shed some light on this class? Thanks.

Charles

I have been meaning to respond to this for some time but been on the road and away from specific sources of information. However, I can fill in a few blanks to try and answer your inquiry.

The Q-4 was the newest and most refined version of the 1600 class locos.

After being placed in service they were very successful but tended to be slippery due to the boiler pressure, drive wheels and factor of adhesion. The boiler pressure was lowered which reduced their tractive effort rating and enhanced their factor of adhesion.

I don't want to try and pull the specifics off the top of my head, but will follow up whenever I can land home long enough to follow through with an answer. I think also that the tenders were enhanced with coal boards for larger coal capacity. They were built with bigger tenders than the earlier 1600's.

I am wondering if this is what you are referring to or if you are menaing comparison of the later 1600's (Q-4's) with earlier versions of that class ?

Ok, time to pick this subject back up....

The Q-1's were the 1500 Class passenger 4-8-4's

The Q-2's were the first group of 4-8-4 fast freight power delivered by Schenectady in 1929 with 70" drivers 28x32 cylinders and 235 lbs boiler pressure. #'s 1601 - 1619

The Q-3's were the 2nd group of fast freight 4-8-4's delivered in 1932 #1620 - 1630.

In 1934 the DL&W went back to Schenectady for a group of 20 engines numbered 1631 - 1650 as the Q-4 class which had 74" drivers and were planned as dual service engines. They were very successful but tended to be slippery with a factor of adhesion of about 3.8 based on their 250# boiler pressure. This was subsequently reduced to 230# reducing their tractive effort from a somewhat unrealistic 72,000 lbs to about 67,000 and a 4.1% factor of adhesion. Three engines, sometime prior to 1950 had their cylinder bores reduced from 28" to 27" and their boiler presure restored to 250# making that a successful conversion. These engines were the 1637, 1645 and 1646.

The 1649 and 1650 received exhaust steam injectors instead of the Worthington SA feed water heaters like the rest of the class.

Driver counter-weights were balanced for 70 mph.

Mods other than boiler presssure setting and cylinder bore reduction were:

Extending the coal bunker boards atop the tender for more fuel capacity
Application of drifting valves sometime in WWII era
Extension of the sand dome capacity noted by the undercut appearance of the dome or flaring at the top.
Application of Mars lights after WWII

1631-1648 were built with Timken roller bearings on engine axles and 1649 & 1650 at SKF... this may have changed during the life time of the locos.

Water capy was 16,000 gallons and original coal capy was 26 tons. I do not know what the increase was in coal capy after the coal boards were raised.

Bore & Stroke was 28 x 32 as built
Total Engine and tender weight 760,000 as built
Stoker: Standard BK
Alco Reverse Gear
Tubes - 82 2-1/4"
Flues 202 3-1/2 " both 21'6" long
Walschaert Valve Gear
Lenth of Engine and Tender 99' 8-1/2" over pulling faces

Thank you. That gives me some numbers to look at. Where this is going is a model. Models were sold as "Original" and "Modern" without any specifics. The numbers provided by you will allow me to do additional research.

Thanks again,

Charles